Search

Background: The purpose of this study was to evaluate the long-term performance of the St. Jude Medical Biocor stented porcine prosthesis in the aortic position. Methods: From January 1985 to December 1996, 455 patients admitted for aortic valve replacement were consecutively enrolled in this study. The mean age was 72.5 ± 9 years, 18 patients (3.5%) had had previous cardiac surgery, and coronary artery bypass grafting was performed in 171 patients (37.6%). Follow-up was complete in 99.6%; up to 21 years were covered. Actuarial event-free rates are given as mean ± standard error and adverse events were classified according to the guidelines for reporting morbidity and mortality after cardiac valvular operations. Results: Cumulative follow-up time was 3,321 patient-years with a mean follow-up of 8.2 years. The actuarial survival rate after 20 years was 9.4% ± 2.8%. The actuarial rates for freedom from structural valve deterioration were 93.1% ± 1.7% at 10 years, 88.4% ± 3.5% at 15 years, and 70.3% ± 10.9% at 20 years. The actuarial rates for freedom from reoperation due to structural valve deterioration were 91.9% ± 1.6% at 10 years, 90.6% ± 2.1% at 15 years, and 86.5% ± 4.5% at 20 years. Conclusions: This study presents one of the largest series of St. Jude Medical Biocor aortic valves in the world. Results indicate an age-dependent risk of structural valve degeneration beginning as soon as 7 years postoperatively for patients below the age of 65 years, but show a low overall incidence of valve-related complications and excellent durability. [Copyright &y& Elsevier]

Background: We asked whether aortic valve replacement using a mechanical prosthesis would allow normalization of left ventricular function and structure in children and young adults. Methods: We performed a clinical follow-up examination in 30 patients with aortic valve replacement at 25 years of age or younger, including conventional and tissue Doppler echocardiography and magnetic resonance imaging. Results: Aortic valve replacement was performed at the median age of 14.3 years (range, 7.6 to 24.3 years) using a mechanical prosthesis (St. Jude Medical; median diameter, 23 mm; range, 17 to 27 mm). Indications were severe aortic stenosis in 6 of 30 patients, aortic regurgitation in 20 of 30 patients, or a combination of aortic stenosis and regurgitation (4 of 30 patients). Aortic valve replacement was a reoperation in 12 of 30 patients who primarily underwent aortic valvotomy at a median of 7.1 years (range, 1.0 to 11.3 years). In-hospital mortality was 0%. Follow-up was a median of 6 years (range, 1.2 to 14.5 years). Twenty-nine of 30 patients were in New York Heart Association functional class I without thromboembolic complications, cerebrovascular accidents, or major bleeding on oral anticoagulation. Left ventricular dilatation before aortic valve replacement was present in 20 of 30 patients but normalized in all but 4 patients on follow-up. Most patients showed a normal end-diastolic volume on magnetic resonance imaging, and 23 of 26 patients showed a normal left ventricular ejection fraction (median, 0.53; range, 0.33 to 0.75). Peak systolic strain of the left ventricular myocardium was a median of −13.3% (range, −0.5% to −31%), and was normal in 28 of 30 patients. Conclusions: Aortic valve replacement in children and young adults offers a good treatment option and may lead to normalization of left ventricular size and function in most patients. [Copyright &y& Elsevier]

Background: Our goal is ambulatory total respiratory and right heart assistance allowing a bridge to lung transplant. To that end, we have coupled a compact paracorporeal gas exchange device with a right ventricular assist device (RVAD) to create an “OxyRVAD.” Methods: Through a limited left thoracotomy, the main pulmonary artery (PA) and right atrium (RA) were exposed in 5 anesthetized sheep. After a systemic heparin bolus, a 12-mm outer diameter crimped graft glued to tubing was anastomosed (end to side) to the main PA and a VAD atrial cannula was placed through the RA appendage. The chest was drained and closed, then the PA graft flowed at 1 to 2 L/min as a shunt to the RA overnight. The next day, the animal was reanticoagulated, and the shunt cannulae clamped and divided. The OxyRVAD unit, consisting of commercially available components including an axial flow pump and low-resistance cardiopulmonary bypass gas exchange device, was interposed. Pumping from RA to PA was maintained at 3 L/min. Results: Five consecutive sheep survived the implant, and stood and ate normally after initiation of the OxyRVAD. Three survived the full 2-week study, and a fourth was sacrificed on day 13 owing to a storm-related power failure. For these 4 sheep, pump flow was stable at 3 L/min. Carbon dioxide removal was constant and total during the experiment at 200 ± 19 mL/min. Oxygen transfer was 144 ± 44 mL/min. One sheep had progressive thrombocytopenia and was sacrificed on day 5 after implant. Conclusions: Our ambulatory OxyRVAD can provide total assistance for the right heart and lungs in normal awake sheep for 14 days. [Copyright &y& Elsevier]

Background: Stentless aortic bioprostheses were shown to be hemodynamically superior to earlier generations of stented bioprostheses. Modern stented valve designs have improved hemodynamics. A prospective randomized controlled trial was undertaken to compare stentless versus modern stented valves. Our aim was to determine any differences in early postoperative clinical and hemodynamic outcomes. Methods: Patients with severe aortic valve stenosis (n = 161) undergoing aortic valve replacement were randomized intraoperatively to receive either the C-E Perimount (Edwards Lifesciences, Irvine, CA) pericardial stented bioprosthesis (n = 81) or the Prima Plus (Edwards Lifesciences) (porcine stentless bioprosthesis (n = 80). Transthoracic echocardiograms were performed at one week and eight weeks postoperatively to assess left ventricular mass (LVM) and transvalvular gradients (TVG). Results: There were no differences between the two groups in baseline characteristics. Cardiopulmonary bypass and ischemic times were longer in the stentless group. Despite similar native aortic annular diameters, the mean size of the prosthesis used in the stentless group was 2.1 mm (SD = 2.8) larger (p < 0.001). Early (30-day) mortality (stentless 3.7% vs stented 2.5%; p = 0.68) and morbidity was similar between groups. Eight weeks postoperatively, LVM (stentless 199 ± 70 vs stented 204 ± 66 grams; p = 0.32) and TVG decreased in both groups (mean systolic gradient; stentless 10 ± 3 vs stented 10 ± 4 mm Hg; p = 0.54) but there was no significant difference between groups. Conclusions: Despite longer ischemic times in the stentless group, early postoperative outcomes were similar. Both stented and stentless aortic valve replacement offers excellent hemodynamics and can be achieved with low perioperative mortality. [Copyright &y& Elsevier]

Background: The stented Soprano valve (Sorin Biomedica S.pA., Saluggia, Italy) is a pericardial tissue valve designed for a totally supra-annular implant with the aim of improving hemodynamic performance, particularly in patients with a reduced aortic annulus. However, its hemodynamics and early clinical outcome are poorly understood. Methods: Seventy-seven patients (mean age 76 ± 5 years, 56% males) underwent aortic valve replacement with the Soprano valve. All patients were monitored with clinical examination and serial echocardiography at 1, 6, and 12 months and yearly afterward. Results: At preoperative echocardiography, average left ventricular outflow tract diameter was 2.1 ± 0.2 cm. At operation, 35% of patients received a 20-mm valve, 54% a 22-mm valve, and 11% a 24-mm valve. At 6-month follow-up, peak and mean transprosthetic gradients were 18 ± 8 and 9 ± 4 mm Hg, respectively; effective orifice area (EOA) and EOA index were 1.84 ± 0.6 cm2 and 0.9 ± 0.2 cm2/m2, respectively. Incidence of patient-prosthesis mismatch (ie, EOA index < 0.85 cm2/m2) was 23%, with no case of severe mismatch (ie, EOA index < 0.6 cm2/m2). In addition, left ventricular hypertrophy showed a significant regression (mass index from 214 ± 98 g to 129 ± 41 g; p = 0.001), and ejection fraction increased (from 58% ± 17% to 67% ± 8%; p = 0.001). Cumulative follow-up was 7.9 months per patient. Thirty-day mortality rate was 2.6% (2 of 77). Cumulative survival at 6, 12, and 24 months was 92% ± 3.7%, 85% ± 5.7%, and 85% ± 5.7%, respectively. Two patients experienced embolic episodes. One case of anticoagulant-related bleeding occurred. Conclusions: In our series, the Soprano bioprosthesis showed a good hemodynamic performance, low incidence of patient-prosthesis mismatch, and favorable early clinical results. [Copyright &y& Elsevier]

Background: Some children who have had an aortic valve replacement (AVR) will need valve re-replacement (redo-AVR). We analyzed our results with 38 redo-AVRs in 30 children. Methods: Thirty children, aged 2 months to 20 years (mean, 11.5 ± 5.4 years), underwent 38 redo-AVRs 1 month to 14 years (mean, 4.6 ± 4.5 years) after previous AVR. Seven children had a second redo-AVR and one had a third redo-AVR (his fourth AVR). Reoperation indication was primarily stenosis in 19, regurgitation in 12, endocarditis in 3, valve thrombosis-emboli in 3, and ruptured aortic aneurysm in 1. The initial valve was mechanical in 26, homograft in 7, xenograft in 4, or a Ross procedure in 1. Sixteen patients (42%) had a previous Konno procedure. Results: The new valve was mechanical (28), homograft (5), xenograft (4), or a Ross procedure (1). Twenty-five valves were upsized on re-replacement. The median valve size was 23 mm (median size increase 4 mm). Twenty-seven operations (71%) included annulus enlargement (16 redo-Konno, 8 new Konno, and 3 Manougian). Twelve children (32%) had concomitant operations including mitral valve repair-replacement (4) and right ventricular outflow tract procedure (5). Three of the 4 hospital deaths were with second or third time redo-AVR. The only death in patients with first time redo-AVR was a patient in cardiogenic shock at the time of operation. Conclusions: Redo-AVR in children can be performed with reasonable morbidity and mortality. A larger prosthesis can often be placed in these children. Second or third time redo-AVR appears to be riskier. Earlier referral before onset of ventricular dysfunction is warranted. [Copyright &y& Elsevier]

Background: This study evaluates the midterm clinical results of valve-preserving aortic root reconstruction by means of a modified conduit incorporating sinuses of Valsalva. Methods: During a 5-year period, 151 patients with aneurysm of the aortic root underwent a reimplantation type of valve-sparing procedure using the Gelweave Valsalva prosthesis that incorporates sinuses of Valsalva. There were 121 males (80.1%), and the mean age was 56.4 ± 14.4 years (range, 14 to 83). Fourteen percent of the patients had Marfan syndrome and 8.6% had bicuspid aortic valve. Seven patients (4.6%) suffered from acute aortic dissection. Aortic replacement was extended to the arch in 14 patients (9.3%). Sixteen patients (10.6%) had associated cusp repair. Results: In-hospital mortality was 3.3%, and it was significantly higher among patients operated on for acute dissection (p = 0.001) and in symptomatic patients (III–IV New York Heart Association class; p = 0.021). Follow-up (mean, 18 months; range, 1 to 60) was 100% complete. There were 2 late deaths. Ten patients (6.8%) had 3 to 4+ aortic regurgitation, and 8 of these required late aortic valve replacement. Cusp repair was associated with a high incidence of late aortic valve replacement (p = 0.005). At 5 years, freedom from aortic valve replacement and freedom from grade 3 to 4 aortic insufficiency was 90.8% ± 3.3% and 88.7% ± 3.6%, respectively. Conclusions: The reimplantation valve-sparing procedure with the Gelweave Valsalva prosthesis provides satisfactory results for patients with aortic root aneurysm. Aortic cusp repair may lead to late aortic insufficiency. Proper leaflet evaluation is of paramount importance in preventing residual valve regurgitation. [Copyright &y& Elsevier]

Background: The ATS Open Pivot Heart Valve was first introduced in 1992 and has been implanted routinely at our institution since 1993. Valve selection was based on surgeon preference. The objective of this study is to retrospectively analyze our 11-year clinical results with ATS prostheses. Methods: Between January 1993 and December 2003, 601 ATS valves (393 aortic valve replacement [AVR], 168 mitral valve replacement [MVR], 20 aortic plus mitral valve replacement [DVR]) were implanted in 581 patients (377 male, 204 female; mean age, 63.7 years; range 18 to 89). Preoperatively, 47 (8%) were New York Heart Association class I, 212 (36.5%) were class II, 267 (46%) were class III, and 55 (9.5%) were class IV. Preoperative comorbidities were coronary artery disease, 167 (29%); diabetes mellitus, 72 (12%); cerebrovascular disease, 2 (0.3%); endocarditis, 53 (9%); and atrial fibrillation, 115 (20%). Results: Follow-up is 99% complete. Data represent 2,500 cumulative patient-years. Mean follow-up is 4.3 ± 2.6 years (range, 0.1 to 11.6). Overall hospital mortality is as follows: AVR, 3.8% (15 patients); MVR, 1.8% (3 patients); DVR, 10% (2 patients). Structural valve failure was not encountered. Overall survival at 10 years is AVR, 84.7% ± 3.1%, AVR plus coronary artery bypass, 67.5% ± 8.2%; MVR, 59.8% ± 7.1%, MVR plus coronary artery bypass, 39% ± 27.8%; and DVR, 74.3% ± 10%. Freedom from valve-related death at 10 years is AVR, 99.2%; MVR, 94.6%; and DVR, 100%. Linearized rates for postoperative complications are paravalvular leak, 0.6% per patient-year; valve thrombosis, 0.04% per patient-year; thromboembolism, 1.1% per patient-year; major bleeding, 0.5% per patient-year; and de novo prosthesis endocarditis, 0.1% per patient-year. Postoperative mortality risk was significantly elevated by diabetes (p < 0.01), but not by other comorbidities. Conclusions: Our 11-year experience demonstrates low rates of adverse events and valve-related complications with the ATS Open Pivot heart valve. [Copyright &y& Elsevier]

Background: Factors predicting long-term survival and reoperative risk after mitral valve repair for subsets with prolapse involving the anterior leaflet in the current era are unclear. Methods: Between January 1, 1980 and December 31, 1999, surgical correction of mitral regurgitation was performed in 2,219 patients. We analyzed a subset of 1,411 patients with isolated mitral regurgitation due to leaflet prolapse undergoing mitral repair or replacement (± coronary bypass). Results: Mean age was 64 years, and 1,003 (71%) were men. Mitral repair was performed in 1,173 (83%) patients. Factors independently predicting overall long-term survival included valve repair, younger age, better functional class, and the absence of significant coronary artery disease. After adjusting for these, smaller preoperative left ventricular end-systolic dimension and greater preoperative ejection fraction were associated with superior survival. Mitral reoperation occurred in 97 patients (75 repairs, 22 replacements), at a mean of 4.8 years after initial procedure. Cumulative risk of reoperation was similar for patients having valve repair or replacement. Factors predictive of need for reoperation after initial repair were younger age, anterior leaflet prolapse, chordal shortening, no leaflet resection, no prosthetic annuloplasty, greater than mild residual mitral regurgitation, and coronary artery disease. After valve replacement, the sole determinant of reoperation was use of a biological prosthesis. The durability of repair for prolapse of the anterior leaflet improved significantly during the second decade of the study. Conclusions: Mitral repair affords superior long-term survival, with permanence comparable with mechanical valve replacement. In all categories of mitral leaflet prolapse, durability of valve repair has improved over the past decade. [Copyright &y& Elsevier]

Purpose: To evaluate the clinical results of a new covered mushroom-shaped metallic stent for managing gastroesophageal anastomotic leak after esophagogastrostomy with a wide gastric tube and gastric pull-up. Description: The stent is a self-expanding prosthesis especially designed for occlusion of the esophago-thoracic anastomotic leaks after esophagogastrostomy. From January 2002 to September 2005, 8 patients with gastroesophageal anastomotic leaks were treated with stents. Information about the technical success of stent placement, definitive closure of leak, stent removal, and complications were obtained. Evaluation: Stent placement was technically successful in all patients, without immediate procedural complications. The stent completely sealed off the fistula in all patients, and 30-day mortality was nil. Follow-ups at 7 to approximately 30 months showed that all leaks were healed without stent-related complications, and the stents were removed after approximately 18 to 48 days. Two patients died, and the remaining 6 patients were alive with no evidence of disease at the time of this report. Conclusions: The use of a new covered mushroom-shaped metallic stent proved expedient, safe, and effective in the treatment of gastroesophageal anastomotic leaks. [Copyright &y& Elsevier]

Background: Previous studies have shown that prosthesis–patient mismatch (PPM) results in higher early and late mortality after bioprosthetic aortic valve replacement. Careful selection of stented bioprostheses was recommended to avoid inadequate effective orifice area. We studied the incidence of PPM and its potential effects on clinical outcome in patients undergoing aortic valve replacement using the Carpentier-Edwards Perimount bioprosthesis. Methods: Independent predictors of early and late mortality and hospital readmission for cardiac reasons were defined in 506 patients (mean age, 73 years; range, 57 to 87 years) by multivariate analysis. Mean follow-up was 6.1 ± 4.8 years; maximum follow-up was 18.6 years. Results: The incidence of severe PPM (effective orifice area index < 0.65 cm2/m2) was 0.2% and of moderate PPM (effective orifice area index > 0.65 and < 0.85) was 20%. Multivariate analysis revealed that moderate PPM was not an independent predictor of early mortality, late mortality, or hospital readmission for cardiac reasons. Reduction of septal hypertrophy was similar in patients with and without moderate PPM. Conclusions: The incidence of severe PPM is virtually nonexistent after aortic valve replacement using the Carpentier-Edwards Perimount valve. Moderate PPM is found in 20% of cases and is clinically irrelevant in this population. [Copyright &y& Elsevier]

Background: It is still controversial as to whether a small prosthesis should be inserted or a small aortic annulus should be enlarged to minimize patient-prosthesis mismatch (PPM). This retrospective study reviewed our strategy for avoiding PPM. Methods: Isolated or combined aortic valve replacement was performed in 181 patients, including 24 patients (13.3%) aged less than 65 years with a small aortic annulus (≤ 21 mm) who underwent enlargement of the annulus by the Manouguian (n = 18) or Nicks (n = 6) procedure. In patients aged 65 years or more, a Carpentier-Edwards Perimount pericardial (CEP) valve was implanted with few exceptions. We assessed our strategy for avoiding PPM by comparison with published normal reference values for the indexed effective orifice area. Results: A CEP valve was implanted in 53 patients, and St. Jude Medical (SJM) mechanical valves were used in 128 patients. A standard 21-mm SJM valve was only used in 4 patients and no 19-mm valves were employed. However, 19-mm CEP valves were used in 12 older patients with a small body surface area (1.43 ± 0.14 m2). No patient receiving an SJM valve had an indexed effective orifice area of 0.85 cm2/m2 or less, and PPM developed in only 2 (3.8%) of 53 patients receiving CEP valves. Consequently, the prevalence of PPM was 1.1%. The 10-year survival rates of patients receiving CEP or SJM valves with or without annular enlargement were similar. Conclusions: The prevalence of PPM was low in patients more than 65 years old with a relatively small body size who received bioprosthetic valves. In patients less than 65 years old with a small annulus, the method of first choice for avoiding PPM is aortic annular enlargement. [Copyright &y& Elsevier]

Background: Normal functioning mechanical heart valve prostheses are designed to have a certain degree of intrinsic structural regurgitation as a washout mechanism to avoid prosthetic thrombosis. However, intrinsic regurgitation leads to blood cell trauma and hemolysis. Information on hemolysis associated with mechanical bileaflet prostheses is scarce. This study evaluated factors influencing hemolysis in 197 Bicarbon mechanical bileaflet prostheses implanted in 164 patients. Methods: Serial office interviews, laboratory studies, and echocardiography evaluations were done in the surviving patients. An assay for measuring lactate dehydrogenase activity was developed, and the presence and severity of subclinical hemolysis was determined using reported criteria and analyzed at 1 and 2 years. Results: Hospital mortality was 5.5%. Follow-up was 98.1% complete. No patient had clinically significant or severe subclinical hemolysis. Serum lactate dehydrogenase levels were significantly higher when a paravalvular leak was documented (282 ± 85 U/L versus 242 ± 64 U/L; p = 0.0026). Subclinical hemolysis was significantly more frequent after mitral valve (p = 0.001) and double valve replacement (p = 0.001) than after aortic valve replacement, and was unrelated to prosthetic size or to geometric area index, even in those cases with effective orifice area index equal to or less than 0.85 cm2/m2 (p = 0.298). Conclusions: Mild subclinical hemolysis is frequently associated with normal functioning Bicarbon heart valves. Subclinical hemolysis was significantly influenced by valve position but not by valve size or effective orifice area index and remained stable through time. The magnitude of hemolysis in Bicarbon prostheses compared favorably with that reported for other bileaflet heart valve prostheses. [Copyright &y& Elsevier]

Background: The 1998 American College of Cardiology/American Heart Association Guidelines recommend mechanical prostheses for valve replacement in patients with end-stage renal disease requiring dialysis. The aim of the study is to evaluate the combined experience at two academic centers. Methods: Sixty-nine valve replacements (aortic 40; mitral 22; multiple 7; 47 bioprostheses, 22 mechanical prostheses) were performed. Total follow-up was 128.7 patient-years (bioprostheses, 68.4; mechanical prostheses, 60.4). Results: Patient populations were homogeneous, except for age (bioprostheses greater than mechanical prostheses, p = 0.012), previous myocardial infarction (bioprostheses greater than mechanical prostheses, p = 0.040), and concomitant CABG (bioprostheses greater than mechanical prostheses, p = 0.019). A survival advantage was observed in favor of mechanical prostheses (p = 0.0299) at 5 years. Freedom from valve-related complications at 5 years was calculated for thromboembolism plus thombosis plus hemorrhage (bioprostheses, 93.0% ± 3.9%; mechanical prostheses, 76.4% ± 12.7%), thromboembolism excluding thombosis (bioprostheses, 93.0% ± 3.9%; mechanical prostheses, 88.9% ± 10.5%), and hemorrhage (bioprostheses, 100%; mechanical prostheses, 95.2% ± 4.7%). One case of structural valve deterioration occurred in the bioprostheses group at 95 months after surgery. Five-year freedom from all valve-related complications was 82.8% ± 8.1% for bioprostheses and 76.4% ± 12.7% for mechanical prostheses. Conclusions: Overall survival was poor. Differences between populations were related to age at operation and coronary artery disease. Structural valve deterioration was not accentuated with bioprostheses. Considering lack of homogeneity between prostheses groups there was no superiority of mechanical prostheses over bioprostheses in terms of freedom from composites of complications. Bioprostheses should be considered in the management of valvular disease in end-state renal disease patients. [Copyright &y& Elsevier]

The optimal approach to early postoperative anticoagulation after mechanical valve implantation remains controversial. This review article examines the pathogenesis of thrombus formation and the different strategies for early postoperative anticoagulation. The most commonly reported anticoagulation regimens had the after estimates of early postoperative thromboembolism and hemorrhage: oral anticoagulation alone (0.9%, 3.3%); oral anticoagulation with intravenous unfractionated heparin (1.1%, 7.2%); and oral anticoagulation with low molecular weight heparin (0.6%, 4.8%). Although intravenous heparin may be associated with a higher incidence of hemorrhage, a randomized trial is needed to provide the best evidence regarding early postoperative anticoagulation after mechanical valve implantation. Nearly four decades have passed since the first mechanical prosthetic valves were implanted. Frequent thromboembolic complications with the first mechanical valves led to recommendations of universal anticoagulation for these patients. Since then, several design changes and modifications have been made to improve the longevity, hemodynamics, and thrombogenicity of newer generation mechanical valves. With improved blood flow, less stasis, and less thrombogenic materials, lower rates of thromboembolism have been reported []. Despite these advances however, thromboembolism and anticoagulant-related bleeding continue to account for 75% of all complications after mechanical valve replacement []. Occurring most commonly within six months after implantation [], these complications can adversely affect mortality and quality of life. Furthermore, the threat of their occurrence creates a psychological burden for each patient with a mechanical valve. The need for life-long anticoagulation in patients with mechanical valves is not in dispute, and the perioperative management of anticoagulation during non-cardiac surgery has been reviewed extensively []. However, the approach to early postoperative anticoagulation after mechanical valve implantation is still a matter of debate. The optimal intensity and timing of anticoagulation to prevent early thromboembolism after valve replacement surgery without postoperative bleeding complications is unknown. Hence, many anticoagulation protocols have been proposed, but a lack of consensus remains. The objectives of this study were (1) to reexamine the pathogenesis of thrombus formation and the need for anticoagulation; (2) to critically review the literature on early postoperative anticoagulation strategies; and (3) provide an estimate of the incidence of bleeding and thromboembolism for each approach to early postoperative anticoagulation. [Copyright &y& Elsevier]

Background: Severe aortic valve stenosis is relatively more prevalent in patients with repeated bleeding episodes. The goal of the present study was to determine the effect of aortic valve replacement on von Willebrand factor levels in patients with aortic stenosis. Methods: Von Willebrand factor levels were assessed by using immunoblotting electrophoresis techniques before and 1 month after surgery in 29 consecutive patients with severe aortic valve stenosis. Results: Eight of 29 patients reported episodes of bleeding, including three episodes of major bleeding, in the 6 months before surgery. None of the patients were receiving anticoagulation therapy. Although there was no difference in platelet count before and after surgery, von Willebrand factor levels were significantly greater at 1 month after surgery (p = 0.05) when compared with preoperative values. Further, von Willebrand factor levels were significantly lower in patients with aortic valve prosthesis mismatch than in those patients without this phenomenon (p < 0.05). Electrophoresis experiments showed a deficit in large multimers of von Willebrand factor preoperatively but not postoperatively, except for in those patients with aortic valve prosthesis mismatch. Conclusions: In conclusion, valve replacement can result in increases in von Willebrand factor in patients with aortic valve stenosis. [Copyright &y& Elsevier]

Background: The purpose of this study was to identify patient subgroups in which prosthesis-patient mismatch most influenced late survival. Methods: Over a 12-year period, 1,400 consecutive patients underwent bioprosthetic (933 patients) or mechanical (467) aortic valve replacement. Prosthesis-patient mismatch was defined as prosthetic effective orifice area/body surface area less than 0.75 cm2/m2 and was present with 11% mechanical and 51% bioprosthetic valves. Results: With bioprosthetic valves, prosthesis-patient mismatch was associated with impaired survival for patients less than 60 years old (10-year: 68% ± 7% mismatch versus 75% ± 7% no mismatch, p< 0.02) but not older patients (p= 0.47). Similarly, with mechanical valves, prosthesis-patient mismatch was associated with impaired survival for patients less than 60 years old (10-year: 62% ± 11% versus 79% ± 4%, p < 0.005) but not older patients (p = 0.26). For small patients (body surface area less than 1.7 m2), prosthesis-patient mismatch did not impact survival with bioprosthetic (p = 0.32) or mechanical (p= 0.71) valves. For average-size patients (body surface area 1.7 to 2.1 m2), prosthesis-patient mismatch was associated with impaired survival with both bioprosthetic (p < 0.05) and mechanical (p< 0.005) valves. For large patients (body surface area greater than 2.1 m2), prosthesis-patient mismatch was associated with impaired survival with mechanical (p< 0.04) but not bioprosthetic (p= 0.40) valves. Conclusions: Prosthesis-patient mismatch had a negative impact on survival for young patients, but its impact on older patients was minimal. In addition, although prosthesis-patient mismatch was not important in small patients, prosthesis-patient mismatch negatively impacted survival for average-size patients and for large patients with mechanical valves. [Copyright &y& Elsevier]

Background: The clinical and experimental use of polyurethane heart valve prostheses has been compromised by thrombosis and calcified thrombus. This is caused in part by the lack of an intact endothelium on these implant surfaces. We hypothesize that endothelial seeding of a polyurethane heart valve leaflet with autologous sheep blood outgrowth endothelial cells (BOECs) could be achieved with cholesterol-modified polyurethane (PU-Chol) to promote BOEC adhesion, thereby resulting in an intact, shear-resistant endothelium that would promote resistance to thrombosis. Methods: Cholesterol-derivatized polyurethane was formulated by bromoalkylation of the urethane nitrogens followed by reactive attachment of mercaptocholesterol. In vitro shear flow studies were carried out comparing BOEC retention on control surfaces versus PU-Chol using forces comparable to those observed in vivo with cardiac valves (75 dyne/cm2). Autologous sheep BOECs were seeded onto PU-Chol before pulmonary leaflet replacement surgery under cardiopulmonary bypass. Studies were terminated at 30 and 90 days followed by retrieval analyses. Results: Blood outgrowth endothelial cell seeding of PU-Chol surfaces resulted in an endothelial monolayer that was positive for von Willebrand factor. Polyurethane-cholesterol demonstrated significantly greater BOEC adhesion under 75 dyne/cm2 shear force in vitro than control polyurethane (75.3% ± 12.3% versus 5.8% ± 3.9%, respectively; p < 0.001). Sheep pulmonary cusp replacements demonstrated retention of seeded BOECs on PU-Chol leaflets with no significant differences in the extent of cellular density comparing unimplanted specimens with explants. Control explants (nonseeded PU-Chol and nonseeded polyurethane) demonstrated no evidence of endothelial recruitment. Conclusions: Polyurethane-cholesterol represents a polyurethane formulation with very high adhesive properties for BOECs under heart valve level shear forces both in vitro and in vivo. [Copyright &y& Elsevier]

Background: Mechanical aortic valves are a possible source of microemboli potentially causing cerebral injury. Therefore, the long-term impact of mechanical aortic valve replacement on neurocognitive function is uncertain. Methods: In this prospective, contemporary study, we followed 32 consecutive patients (aged 51 ± 8 years; range, 38 to 70; EuroSCORE [European System for Cardiac Operative Risk Evaluation] 4.4 ± 1.7) undergoing isolated aortic valve replacement with a mechanical prosthesis. A cohort of age- and sex-matched patients (n = 28, aged 50 ± 7 years) served as nonsurgical controls. After aortic valve replacement, neurocognitive function was serially reevaluated at 7-day (n = 32), 4-month (n = 31), and 3-year (n = 29) follow-up. Neurocognitive function was measured by means of P300 auditory evoked potentials. Results: Before the operation, P300 peak latencies were comparable between surgical patients (361 ± 32 ms) and nonsurgical controls (365 ± 33 ms, p = 0.783). In patients undergoing aortic valve replacement, P300 peak latencies were prolonged 7 days after surgery (380 ± 32 ms) as compared with before the operation (361 ± 32 ms, p < 0.0001) and as compared with nonsurgical controls (364 ± 34 ms, p = 0.002). At 4-month (369 ± 30 ms, p = 0.752) and 3-year (370 ± 31 ms, p = 0.825) follow-up, P300 peak latencies normalized as compared with before operation and as compared with nonsurgical controls (4-month follow-up 363 ± 31 ms, p = 0.832; 3-year follow-up 366 ± 32 ms, p = 0.432). We found no difference in patients with different valve types. Conclusions: Despite previous assumptions based on the potential occurence of microemboli in patients with mechanical valves, mechanical aortic valve replacement has no adverse long-term impact on neurocognitive function. This finding is only valid for patients with a comparable age range undergoing isolated aortic valve replacement. [Copyright &y& Elsevier]

Background: Pericardial prostheses have been used as valvular substitutes since 1975. They combine excellent hemodynamic characteristics with a low risk of valve failure during long-term observation. The aim of this article is to describe the clinical long-term performance of the Mitroflow Synergy pericardial valve (Sorin Group Inc, Mitroflow Division, Vancouver, Canada) in the aortic position for as long as 19 years. Methods: Data were obtained between February 1985 and April 2004 from patients with aortic heart valve replacements (n = 1,464) or from patients with replacements of existing prosthetic aortic valves (n = 52). The age group distributions are less than 70 years (n = 175); 70 to 74 years (n = 462); 75 to 79 years (n = 532); 80 to 84 years (n = 273); and greater than or equal to 85 years (n = 74). The cause of the aortic valve lesions was combined (insufficiency and stenosis) in the majority of patients (62.4%). Concomitant procedures were performed in 897 patients (59.2%) and coronary artery bypass grafting was the most common (53.5%). Mean follow-up was 5.5 ± 0.09 years. Total follow-up was 8,408 patient-years. Results: The early mortality (30 days) was 6.6% (n = 99) and late deaths were 60.8% (n = 921). Actuarial event-free rates at 5, 10, and 15 years of follow-up are given as mean ± standard error for endocarditis: 96.9 ± 0.5, 92.8 ± 1.2, and 92.0 ± 1.4, respectively; embolism: 96.7 ± 0.6, 88.8 ± 1.7, and 82.9 ± 3.5, respectively; bleeding: 98.5 ± 0.4, 97.2 ± 0.6, and 94.4 ± 1.7, respectively; structural valve deterioration: 99.0 ± 0.3, 82.8 ± 2.2, and 62.8 ± 5.8, respectively; and reoperation: 98.2 ± 0.4, 79.2 ± 2.4, and 63.4 ± 5.3, respectively. The rate of endocarditis, structural valve degeneration, and reoperation was lower in patients 75 years of age and older compared with younger patients, whereas embolism occurred more frequently in elderly than in younger patients. Conclusions: Adverse events after implantation of Mitroflow aortic bioprosthesis rarely occurred during the first 5 years after valve replacement. The results of the prosthesis indicates reliable long-term morbidity rates and good durability in patients 75 years of age and older. [Copyright &y& Elsevier]

Purpose: Downsizing pulsatile devices requires an increase of beat rate if flow capacity is to be maintained. We applied this concept to the preclinical MagScrew total artificial heart (TAH).Description: The device fills passively with a stroke volume of 45 ml and beat rates up to 250 beats per minute (bpm).Evaluation: Stable hemodynamics were observed during a 30-day bovine implant with a flow of 8.7 ± 1.2 L/min at beat rates of 204 ± 18 bpm. Device filling was exceptional up to 250 bpm generating flow of greater than 12 L/min. Beat rate adapted to preload in a way similar to a Frank-Starling response. Left and right atrial pressures were balanced. The aortic pulse pressure was 49–70 mm Hg, which translates to a pulsatility index of 0.49–0.77. Organ functions were preserved and blood damage did not occur.Conclusions: Increasing the beat rate while downsizing the MagScrew TAH was successful with strong flow generation by passive filling. Pulsatility was maintained at high beat rates. This innovative approach may be used to develop small pulsatile pumps. [Copyright &y& Elsevier]

Background: The Sorin Slimline aortic valve prosthesis, a modification of the Sorin Bicarbon valve with increased internal orifice diameter and geometric orifice area, may show improved hemodynamic performance when compared with other previous prosthesis, but so far no comparison study has been reported. Methods: Between May 1999 and March 2002, 80 patients (31 to 81 years of age; mean, 65 years) with a small aortic annulus were randomized to undergo aortic valve replacement with either the Sorin Slimline (n = 40) or St. Jude High Performance (n = 40) valve prosthesis. Clinical and echocardiographic Doppler follow-up was performed at 3 to 4 weeks, and 6 and 12 months postoperatively. Results: One patient died of non–valve-related causes 9 months after operation. Mean and peak pressure gradients at 6 and 12 months in the Sorin Slimline valve were lower than in the St. Jude High Performance valve for both size 19 and 21 mm. Effective orifice area and effective orifice area index were not significantly different. There was a significant (p = 0.0001) reduction in left ventricular mass and left ventricular mass index between preoperative measurements and at 12 months after surgery for both valves, but there was no difference (p = 0.27) between the Sorin Slimline and St. Jude High Performance valve prosthesis at any other follow-up period. Clinical results showed similarly good results with both valves. Conclusions: No clinically significant difference in the hemodynamics of both valves was appreciated; patients with a Sorin Slimline valve exhibited statistically significantly lower pressure gradients, but the small differences in effective orifice area and effective orifice area index did not reach significance. A significant left ventricular mass regression was observed with both valve models. Both prostheses provided a satisfactory clinical outcome. [Copyright &y& Elsevier]

Background: Undersized annuloplasty is commonly used in the treatment of functional mitral regurgitation. However, in the case of severely dilated ventricles, annuloplasty may be inadequate to counteract leaflet tethering. My colleagues and I hypothesized that modifying the shape of the annular prosthesis to account for the specific anatomy of functional mitral regurgitation could challenge extreme leaflet tethering.Methods: Using finite element model simulations, we tested valve competence after the implantation of conventional D-shaped versus dog bone–shaped annuloplasty rings, the latter of which was designed to selectively reduce the septolateral dimension of the annulus. Three models were compared: model A, simulating the native mitral valve; model B, simulating the same valve after annuloplasty with a conventional D-shaped annuloplasty; and model C, simulating a dog-bone annuloplasty ring implantation. Each model was then challenged by progressively pulling the tip of the papillary muscles away from the annulus plane to simulate ventricular remodeling and leaflet tethering. Valve competence was compared in each model for each degree of leaflet tethering.Results: After maximal leaflet tethering simulation (4-mm apical displacement of the papillary tips), the regurgitant area increase was 70.4 mm2 for model A and 52.9 mm2 for model B. In model C, the regurgitant area was only negligibly affected by papillary displacement, increasing to 3.9 mm2.Conclusions: An annular prosthesis with selective reduction in the septolateral dimension is more effective than a conventional prosthesis for treating leaflet tethering in functional mitral regurgitation. Use of disease-specific annular prostheses is needed to improve the results of valve reconstruction. [Copyright &y& Elsevier]

Background: Valve prosthesis-patient mismatch is a frequent problem in patients undergoing aortic valve replacement and its main hemodynamic consequence is to generate high transvalvular gradients through normally functioning prosthetic valves. The persistence of high gradients may hinder or delay the regression of left ventricular hypertrophy after aortic valve replacement.Methods: The aim of the study was to determine the impact of prosthesis-patient mismatch on the postoperative regression of left ventricular mass.Left ventricular mass was measured by Doppler echocardiography in 109 patients undergoing aortic valve replacement with a single type of bioprosthesis (Carpentier-Edwards Perimount) for pure aortic stenosis. Prosthesis-patient mismatch was defined as a projected indexed effective orifice area less than 0.90 cm2/m2. On this basis, 58/109 (53.2%) patients had prosthesis-patient mismatch.Results: There was a good correlation (r = 0.61, p < 0.001) between the postoperative mean transprosthetic gradient and the projected indexed effective orifice area. The absolute and relative left ventricular mass regression was significantly (p = 0.002 and p = 0.01, respectively) lower in patients with prosthesis-patient mismatch (-48 ± 47 g, -17% ± 16%) compared to those with no prosthesis-patient mismatch (-77 ± 49 g, -24% ± 14%). In multivariate analysis, a larger projected indexed effective orifice area, female gender and a higher preoperative left ventricular mass are independent predictors of greater left ventricular mass regression.Conclusions: This study shows that in patients with pure aortic stenosis prosthesis-patient mismatch is associated with lesser regression of left ventricular hypertrophy after aortic valve replacement. These findings may have important clinical implications given that prosthesis-patient mismatch is frequent in these patients. [Copyright &y& Elsevier]

Background: There are an increasing number of reports concerning mitral valve repair by means of reconstruction of the chordae tendinae with expanded polytetrafluoroethylene (e-PTFE) sutures. However little information is available about extended application or results of this technique for extended prolapse of posterior mitral leaflets.Methods: Between March 1994 and December 2000, 22 patients with moderate-to-severe mitral regurgitation (MR) as the result of a prolapse of posterior leaflets (age range, 39–73 years) underwent mitral valve repair by means of reconstruction of artificial chordae with 4-CV e-PTFE sutures without leaflet resection. Either Kay''s suture or ring annuloplasty was also performed to correct annular dilatation in all patients.Results: No operative death or late mortality was observed. Before discharge immediate postoperative echocardiography indicated less than moderate MR in 20 out of 22 patients. The follow-up was complete in all cases by clinical examination and serial echocardiograms and the median follow-up period was 87 months (range 24–108). There were two failures that required reoperation because of unsuccessful repair and worsening MR (elongation of the anchored side of the papillary muscle). When the reoperated patients were excluded from the follow-up data, the degree of MR, estimated by echocardiography that was performed at a recent follow-up period, was nonexistent in 6 patients, trivial in 10 patients, and mild in 4 patients. The systolic and diastolic dimensions of the left ventricle decreased significantly (p < 0.01).Conclusions: Replacement of the artificial chordae was not complicated and seemed to preserve favorable relationships among leaflet tissues, chordae, and papillary muscles. We therefore suggest that the extensive use of PTFE artificial chordae seems to be a promising procedure regarding the repair of many kinds of mitral lesions causing MR. [Copyright &y& Elsevier]

: BackgroundMitral valve replacement with prosthetic valves in infants and children requires consideration of multiple variables. When we examined our late follow-up, the effect of the growth of the patient relative to the size of the prosthesis placed was the most important variable predicting late successful results. We reviewed our experience with mitral valve replacement using the Starr-Edwards ball valve in children aged 5 years or younger, focusing on the effect of valve prosthesis–patient mismatch on the long-term results in the growing patient.: MethodsFrom August 1974 to June 1986, 8 patients aged 5 years or younger underwent mitral valve replacements using the Starr-Edwards prosthesis size 0M in 3 patients and 1M in 5 patients. Model 6320 was used in 1 patient and Model 6120 in the remaining 7 patients.: ResultsFollow-up was 100% from 15 to 27 years (mean, 20 years). No valve-related complications of thromboembolism, anticoagulant-related hemorrhage, or prosthetic valve endocarditis were seen. All patients normally developed to adult size. The range of the valve area index of the 3 patients who received the smaller Starr-Edwards valve (size 0M) was 0.97 to 1.24 cm2/m2. Although this size valve was adequate for patient growth to adolescence, in each case valve replacement with a larger valve was required.: ConclusionsOur long-term review of Starr-Edwards ball valve mitral valve replacement in children aged 5 years or younger shows that the Starr-Edwards ball valve (Models 6320 [1 patient] and 6120 [7 patients]) showed excellent durability, no thromboembolism, and no anticoagulant-related complications. Size 0M valves required replacement for hemodynamic reasons because of patient growth; larger size 1M valves remained hemodynamically satisfactory in spite of patient growth. [Copyright &y& Elsevier]

A neonate with truncus arteriosus (type 1) and interrupted aortic arch (type A) associated with an excessively large gap between interrupted aortic segments underwent successful reconstruction of the aortic arch with a partial subclavian flap aortoplasty plus bovine jugular patch (Contegra 200, Medtronic, Inc, Minneapolis, MN) using continuous selective low-flow cardiopulmonary bypass without circulatory arrest. The ventricular septal defect was closed with a Dacron (IMPRA, Inc, Tempe, AZ) patch, and a Contegra prosthesis was used to re-establish right ventricle to pulmonary artery continuity. At an 18-month follow-up, the patient was free of symptoms with normal development. Echocardiography revealed a widely patent aortic arch and an unobstructed right ventricle to pulmonary artery connection. [Copyright &y& Elsevier]

Patients with mechanical aortic valves that develop refractory heart failure may require left ventricular assist devices. These patients have an increased risk of postoperative thromboembolic events due to intermittent valve opening. Previously described techniques to address this problem can result in a significantly increased ischemic time. We describe a simple but novel technique to close the mechanical aortic prosthesis in an expeditious manner. [Copyright &y& Elsevier]

Bridge-to-bridge experience has documented the feasibility of a switch from short-term to long-term mechanical circulatory support until heart transplant. We describe a case of irreversible cardiogenic shock due to giant cell myocarditis treated consecutively with extracorporal membrane oxygenation, bi-ventricular assist device, and total artificial heart. The postoperative course was complicated by human leukocyte antigen sensitization and heparin-induced thrombocytopenia type II. Our patient successfully underwent heart transplant after 10 months of support and was discharged in good condition. This case illustrates suitable device selection for myocarditis and represents two treatable immunological complications. [Copyright &y& Elsevier]

The EXCOR Berlin Heart (Berlin Heart, Berlin, Germany) was successfully used as a pediatric left ventricular assist device as a bridge to cardiac transplantation. The pneumatically driven paracorporeal device successfully supported a 7 kg patient for 53 days until a suitable heart was obtained for transplantation. [Copyright &y& Elsevier]

Bridge to transplant is a well-known strategy to enable patients with congestive heart failure to live until transplant. A 15-year-old boy with Beckers’ muscular dystrophy and cardiomyopathy was accepted for heart transplantation. He suffered a cardiac arrest and was placed on extracorporeal membrane oxygenator. A paracorporeal biventricular assist device and a total artificial heart were considered for bridge to transplant. A CardioWest total artificial heart was chosen because of the patient’s size. Multiple left ventricular thrombi were identified at the time of the ventriculectomy. The patient did well with the total artificial heart was transplanted and discharged home. The unknown presence of significant left ventricular thrombi raises the question of outcome with a paracorporeal ventricular assist device. [Copyright &y& Elsevier]

Herein we describe a case of atypical coarctation of the thoraco-abdominal aorta associated with mucopolysaccharidosis VII in a 4-year-old girl. Aortography showed diffuse narrowing of the descending aorta. An extra-anatomic bypass was constructed using an 8-mm Dacron graft (Meadox Medicals Inc, Oakland, NJ) between the proximal and distal portion of the descending aorta. Balloon angioplasty was necessary to treat stenoses in the infrarenal abdominal aorta. Two years postoperatively at age 6, aortography revealed no stenosis at the anastomotic sites or in the prosthesis, but the hypoplastic segment of the descending aorta between the anstomoses was completely occluded. [Copyright &y& Elsevier]

We present a rare case of a patient diagnosed with aortic insufficiency grade III and a giant coronary artery aneurysm with a maximum diameter of 12 cm. Surgical intervention revealed an incompetent bicuspid aortic valve and a huge thrombosed aneurysm, which communicated with the aorta through the left coronary ostium. In addition to direct closure of the ostium, a saphenous vein was anastomosed to the left anterior descending artery, and the aortic valve was successfully replaced with a mechanical valve. [Copyright &y& Elsevier]

Pulmonary venous obstruction is a rare complication after total cavopulmonary connection by intraatrial grafting. We experienced this complication in two patients. In one of them, a large prosthesis produced inflow obstruction of the dominant ventricle and was successfully replaced with a smaller tube. In the other patient, the intraatrial tube had become severely adherent to the common pulmonary venous orifice and was removed entirely. Conversion to an extracardiac Fontan circulation was later successfully established. [Copyright &y& Elsevier]

Pediatric cardiac surgery began with Dr Gross’s first successful ligation of a patent ductus arteriosus on August 8, 1938, at the Children’s Hospital in Boston. The beginnings of open-heart surgery for repair of congenital malformations, aside from Gibbon’s first successful closure in Philadelphia of an atrial septal defect using an artificial heart-lung machine, can be traced to members of the Department of Surgery at the University of Minnesota during the fifties and sixties of the 20th century. This story will be told, and other advances will be discussed, some of which also carry the imprint of the Minnesota surgical training program, with its heavy emphasis on research. [Copyright &y& Elsevier]

Background: Previous thoracic artificial lungs (TALs) had blood flow impedance greater than that of the natural lungs, which could cause abnormal pulmonary hemodynamics. New compliant TALs (cTALs), however, have an impedance lower than that of the natural lung., Methods: In this study, a cTAL of new design was attached between the pulmonary artery (PA) and the left atrium (LA) in 5 sheep (60.2 ± 1.9 kg). A distal PA band was placed to control the percentage of cardiac output (CO) routed to the cTAL. Rest and exercise conditions were simulated using a continuous dobutamine infusion of 0 and 5 μg/kg/min, respectively. At each dose, a hemodynamic data set was acquired at baseline (no flow to the cTAL), and 60%, 75%, and 90% of CO was shunted to the cTAL., Results: Device resistance did not vary with blood flow rate, averaging 0.51 ± 0.03 mm Hg/(L/min). Under all conditions, CO was not significantly different from baseline. Pulmonary system impedance increased above baseline only with 5 μg/kg/min of dobutamine and 90% of CO diverted to the cTAL., Conclusions: Results indicated minimal changes in pulmonary hemodynamics during PA-LA cTAL attachment for high device flows under rest and exercise conditions., (Copyright © 2012 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Mitral valvuloplasty using Gore-Tex (W.L. Gore & Associates, Inc, Flagstaff, AZ) as artificial chordae is often associated with difficulties in determining the length of the artificial chordae, as well as preventing knot slippage, especially for patients with broad anterior leaflet prolapse. We describe a simple technique that enables surgeons to easily determine the correct length of the artificial chordae and tie slippery knots without using a specific device., (Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: End-stage lung disease patients who require a thoracic artificial lung (TAL) must be extubated and rehabilitated prior to lung transplantation. The purpose of this study is to evaluate hemodynamics and TAL function under simulated rest and exercise conditions in normal and pulmonary hypertension sheep models., Methods: The TAL, the MC3 Biolung (MC3, Inc, Ann Arbor, MI), was attached between the pulmonary artery and left atrium in nine normal sheep and eight sheep with chronic pulmonary hypertension. An adjustable band was placed around the distal pulmonary artery to control the percentage of cardiac output (CO) diverted to the TAL. Pulmonary system hemodynamics and TAL function were assessed at baseline (no flow to the TAL) and with approximately 60%, 75%, and 90% of CO diverted to the TAL. Intravenous dobutamine (0, 2, and 5 mcg . kg(-1). min(-1)) was used to simulate rest and exercise conditions., Results: At 0 and 2 mcg . kg(-1). min(-1), CO did not change significantly with flow diversion to the TAL for both models. At 5 mcg . kg(-1). min(-1), CO decreased with increasing TAL flow up to 28% +/- 5% in normal sheep and 23% +/- 5% in pulmonary hypertension sheep at 90% flow diversion to the artificial lung. In normal sheep, the pulmonary system zeroth harmonic impedance modulus, Z(0), increased with increasing flow diversion. In hypertensive sheep, Z(0) decreased at 60% and 75% flow diversion and returned to baseline levels at 90%. The TAL outlet blood oxygen saturation was 95% or greater under all conditions., Conclusions: Pulmonary artery to left atrial TAL use will not decrease CO during rest or mild exercise but may not allow more vigorous exercise., (Copyright 2010 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: There is no mechanical device available to support patients with end-stage lung failure for weeks and months until appropriate donor organs for lung transplantation are available., Methods: In a 38-year-old female patient with primary pulmonary hypertension a paracorporeal artificial lung (PAL) system was placed parallel to the pulmonary circulation with connections to the pulmonary artery and to the left atrium. The key component of the PAL was a low-resistance membrane oxygenator., Results: After institution, the PAL had a blood flow of 3.5 L/min and created a PaO(2)/fraction of inspired oxygen ratio of 270, while the oxygenator was provided with oxygen 3 L/min. The pulmonary artery pressure declined by almost 50%. The PAL worked well over 62 days until appropriate donor lungs were available. With resuming more physical activity, an increased flow through the native lung augmented the fraction of unsaturated blood arriving at the left atrium, which mandated increasing oxygen flow to the PAL., Conclusions: The data obtained with this case encourage further research into PAL systems, which may hopefully serve as a bridge to lung transplant device in appropriate patients in the future.

Background: Thirty-day testing of the MC3 Biolung (MC3 Inc, Ann Arbor, MI) total artificial lung (TAL) was performed to prepare for future clinical testing., Methods: TAL inlet and outlet grafts were sewn to the pulmonary artery and left atrium of 8 sheep (35.6 +/- 1.6 kg), and the TAL was attached the next day. Hemodynamic and sheep blood gas data were measured every 1 to 4 hours. TAL blood gases were measured twice daily, and organ function was assessed three times per week. The TAL was replaced if its resistance increased 300% or if the oxygen content difference across the TAL decreased 25% versus baseline. After 30 days, the sheep were euthanized and necropsied., Results: Five sheep survived 30 days. Three sheep were euthanized before 30 days due to bleeding, mechanical graft failure, or gastric distress. Survivors had normal, stable hemodynamics and blood gases. Average device use was 9.5 +/- 2.1 days. TAL oxygen transfer was 108 +/- 9.2 mL/min with 51% +/- 6.3% of cardiac output flowing to the TAL. TAL resistance and flow were 1.3 +/- 0.3 mm Hg x min/L and 2.4 +/- 0.2 L/min at baseline versus 2.6 +/- 0.9 mm Hg x min/L and 2.0 +/- 0.2 L/min for the remaining 30 days. Platelet and white blood cell counts increased 88% and 84% from baseline, respectively, after 10 days and were stable thereafter. Ischemic lesions in the kidney were seen in most sheep at necropsy, but organ function was normal., Conclusions: Thirty-day respiratory support was feasible with the Biolung, but improvements in biocompatibility and anticoagulation regimen are warranted to reduce the thrombogenicity of the device.

Background: A thoracic artificial lung, the MC3 Biolung, is being developed as a bridge to lung transplantation or as a treatment for acute respiratory insufficiency., Methods: The thoracic artificial lung was tested in 10 sheep with the goal of 7 days of respiratory support. The sheep were recovered from surgery and monitored awake for 7 days. Hemodynamics, blood gases, blood cell counts, and organ function were recorded, and after 7 days, all sheep were euthanized and necropsied., Results: Seven sheep survived the full duration. Cardiac output and mean arterial blood pressure were unchanged, averaging 4.7 +/- 0.8 L/min and 98 +/- 10 mm Hg, respectively. Arterial oxygen tension and device oxygen transfer rate were also unchanged, averaging 110 +/- 26 mm Hg and 97.7 +/- 35 mL/min, respectively. Arterial carbon dioxide tension was within normal ranges during the entire experiment, averaging 37.4 +/- 3.8 mm Hg. Artificial lung blood flow decreased from 51% +/- 14% of cardiac output on day 1 to 30% +/- 16% by day 7 because of changes in natural and artificial lung resistance. White blood cell counts were significantly elevated on days 5 and 7, and lastly, kidney and liver function remained normal, although signs of kidney infarction or hemorrhage were noted., Conclusions: The thoracic artificial lung is suitable for 7-day attachment, but improvements in blood biocompatibility are warranted.

Replacement of diseased chordae with Gore-Tex sutures (W. L. Gore & Assoc, Flagstaff, AZ) in patients with degenerative mitral valve insufficiency has become a standard technique used by surgeons in mitral valve repair with good long-term results. Nevertheless, determining the correct length of the artificial chordae has remained problematic. Although various procedures have been previously published, in this article we describe our approach used to achieve an accurate chordal height adjustment.

Background: Our low-impedence, paracorporeal artificial lung (PAL) prototype is well-tolerated in-series with the normal sheep pulmonary circulation. Using our lethal dose 80% to 100% smoke/burn acute respiratory distress syndrome (ARDS) sheep model, we compared PAL to volume-controlled mechanical ventilation (VCMV) in a prospective, randomized, controlled, unblinded, 5-day outcome study., Methods: Fourteen sheep were randomized to PAL (n = 8) versus VCMV (n = 6) to assess outcome. For PAL, arterial cannulas were anastomosed to the proximal and distal main pulmonary artery with an interposing snare diverting full flow through a paracorporeal loop. Acute respiratory distress syndrome was induced in both groups (48 breaths smoke insufflation, third degree burn on 40% of total body surface area). When acute respiratory distress syndrome criteria were met (24 to 30 hours after injury), the PAL was interposed in the paracorporeal loop. Both groups were managed with a VCMV algorithm minimizing tidal volume, ventilator rate, and fractional inspired concentration of oxygen (FiO2)., Results: Six of eight PAL versus 1 of 6 VCMV sheep survived the 5-day study. In PAL, cardiac output, mean arterial pressure, pulmonary artery pressure, left atrial pressure, and central venous pressure remained stable. Average PAL gas transfer was 218.6 +/- 17.7 mL/min O2 and 183.0 +/- 27.8 mL/min CO2. Ventilator settings 48 hours after lung injury in PAL were significantly lower (p < 0.05) than VCMV (TV 210 versus 425 mL; respiratory rate 6 versus 29 breaths/min; minute ventilation 1.2 versus 10.8 L/min; FiO2 21 versus 100%). Likewise, PaO2/FiO2 ratio was normalized in PAL and still met acute respiratory distress syndrome criteria in VCMV. The PAL wet/dry ratio was significantly lower than VCMV (6.36 +/- 0.63 versus 11.85 +/- 1.54; p = 0.008)., Conclusions: In a prospective, randomized, controlled, unblinded, outcomes study, PAL decreased ventilator-induced lung injury in a lethal dose 80% to 100% ARDS model to improve 5-day survival.

Background: We previously reported a 50% incidence of immediate right heart failure using a rigidly housed, noncompliant inflow artificial lung in series with the pulmonary circulation in a healthy ovine survival model. Three device modifications resulted: (1) an inflow cannula compliance chamber, (2) an inlet blood flow separator, and (3) modification of the artificial lung outlet geometry, all to reduce resistance and mimic the compliance of the pulmonary vascular bed., Methods: In 7 sheep, arterial grafts were anastomosed end-to-side to the proximal and distal main pulmonary artery, with the paracorporeal artificial lung interposed. A pulmonary artery snare between anastomoses diverted full pulmonary blood flow through the artificial lung for up to 72 hours., Results: Six of 7 sheep exhibited good cardiac function throughout the test period: mean central venous pressure was 6.8 mm Hg (range, 4 to 11 mm Hg), mean cardiac output, 4.17 +/- 0.12 L/min (range, 2.4 to 6.3 L/min); before and after device mean pulmonary arterial pressure, 21.8 and 18.5 mm Hg, and left atrial pressure, 10.8 mm Hg., Conclusions: This modified artificial lung prototype with an inflow compliance chamber, blood flow separator, and modified outlet geometry has greatly improved cardiac function and initial survival in our healthy ovine model.

Background: An artificial lung with 1 to 6 month work life could act as a bridge to transplantation. A pumpless artificial lung has been developed., Methods: The artificial lung was placed in series with the native lungs of adult sheep. Hemodynamics were observed, as the right ventricle generated flow through the device. Through a left thoracotomy, two 20-mm grafts were anastomosed in an end-to-side fashion to the pulmonary artery. The grafts were externalized, and directed flow through the chest wall, to the extracorporeal lung. The animals were recovered, weaned from the ventilator, and when standing, flow was diverted through the device., Results: Five of 7 animals survived 24 hours with 75% to 100% of the cardiac output diverted through the device. All animals were active, with interest in food and water, and able to stand., Conclusions: The right ventricle perfused the artificial lung with 75% to 100% of the cardiac output for 24 hours. This device demonstrates the feasibility of a pumpless pulmonary assist device relying on the right ventricle for perfusion.

Jointly developed by members of the American Society for Artificial Internal Organs and the Society of Thoracic Surgeons along with staff from the Food and Drug Administration, the National Heart, Lung and Blood Institute and other experts, this recommendation describes the reliability considerations and goals for Investigational Device Exemption and Premarket Approval submissions for long-term, mechanical circulatory support systems. The recommendation includes a definition of system failure, a discussion of an appropriate reliability model, a suggested in vitro reliability test plan, reliability considerations for animal implantation tests, in vitro and animal in vivo performance goals, the qualification of design changes during the Investigational Device Exemption clinical trial, the development of a Failure Modes Effects and Criticality Analysis, and the reliability information for surgeons and patient candidates. The document will be periodically reviewed to assess its timeliness and appropriateness within five years.