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Sclerosing mediastinitis is an uncommon disease associated with a multiplicity of clinical syndromes. The cause of this disorder is probably an abnormal fibroproliferative response to an inflammatory stimulus, most commonly [...]

The impact of newer and more expensive technologies upon the cost of cardiac surgery is a growing concern. It has been suggested that membrane oxygenators of a variety of types have differenct characteristics which may affect patient outcome and the postoperative course and thus the cost of care.

This study was designed to determine the prevalence of Chlamydia pneumoniaein carotid artery plaques. Although there have been numerous studies evaluating coronary plaques for this bacterium fewer studies have assessed noncoronary vasculature. In addition we wished to evaluate whether correlation exists between the presence of C. pneumoniaein carotid plaques and established risk factors for atherosclerosis. Sixty intact carotid artery plaques removed during surgery (carotid endarterectomy) were formalin-fixed and paraffin-embedded according to conventional techniques. These samples were evaluated by polymerase chain reaction analysis to detect presence of C. pneumoniaeDNA. Results were tabulated and compared against established risk factors for atherosclerosis: diabetes, hypertension, hyperlipidemia, age, and smoking. Forty-two (70.0%) of the 60 plaques that were evaluated tested positive for the presence of C. pneumoniaeDNA by polymerase chain reaction analysis. In the sample defined as being from heavy smokers (greater than 15-pack-year history) 33 (94.3%) of 35 plaques tested positive whereas two (5.7%) tested negative. This correlation demonstrated statistical significance (P= 1.36 x 10–6, two-tailed Fisher exact test). Presence of C. pneumoniaein carotid plaques demonstrated no statistically significant correlation with diabetes, hypertension, or hyperlipidemia. Age as a risk factor was examined but not statistically evaluated because of the narrow range within our patient sample. Analysis of the data reveals that C. pneumoniaeis present in large numbers of atheromatous plaques as is consistent with emerging data. What is interesting though is that 33 (94.3%) of the 35 smokers had plaques that tested positive for the bacterium as opposed to only nine (36.0%) of the 25 nonsmokers. Identification of specific populations exhibiting a high prevalence of C. pneumoniaemay serve to focus future studies. Ongoing investigation will seek to determine whether C. pneumoniaeplays an active role in the pathogenesis of atherosclerosis.

This paper presents an unusual case of an individual with myocardial ischemia, angina pectoris, and myocardial infarction who also had an anaphylactic reaction to angiographic dye.

• The replamineform process allows fabrication of microporous prostheses with control of both pore diameter and structural geometry by means of a variety of biomaterials. Tubular prostheses 3 cm long, 6 mm inside diameter, and 1 mm wall thickness were made of Silastic or Bioelectric Polyurethane (BEP) with use of a template of the echinoderm Heterocentrotus mammillatus. Pore diameter of the prosthesis wall was 18 to 25 μ. Light and scanning-electron microscopy of grafts removed between 1 and 32 weeks demonstrated that organization and endothelialization of neointima were similar for both polymers, being complete by 4 to 8 weeks. However, the character of prosthesis wall ingrowth was strikingly different: the microporous lattice of BEP was completely ingrown early, but was apparently fragmented by continued granulomatous inflammation by 32 weeks, while Silastic generated minimal inflammatory response and slower fibrous tissue and capillary ingrowth. Thus, with Silastic and BEP, similarities in neointima organization appeared independent of distinct differences in wall ingrowth. The replamineform process is a unique means of studying surface healing and wall ingrowth of different biomaterials as microporous vascular prostheses in a controlled fashion.(Arch Surg 114:698-702, 1979)

The Symposium on Vascular Grafts contains reports taken from The Society for Vascular Surgery and The International Cardiovascular Society meeting held in 1978. They have been assembled to provide an overview of the state of the art of vascular prostheses, including where we presently stand and where the future of prosthetic development and study lies, with particular regard to potential research areas.At the outset, we would like to emphasize that the following symposium is not all-inclusive, nor was it meant to be. The symposium group was made up of persons who submitted material for the 1978 program. There is certainly a great deal of additional interest and expertise, and many other investigators are working on other materials and techniques.1-6 THE GRAFT The ideal vascular graft should be immediately available in many sizes and shapes. It should be biocompatible, allowing healing with a nonthrombogenic surface. It should have a

• The Doppler ultrasonic flowmeter was used to determine intestinal serosal and mesenteric blood flows in 130 patients who underwent abdominal aortic vascular procedures and in 14 patients who underwent general surgical procedures. Temporary occlusion of the inferior mesenteric artery (IMA) during aortic surgery resulted in the absence or marked diminution of collateral blood flow over the left side of the colon in eight patients. One patient had the flow in the IMA preserved by proper placement of an end-to-side aortofemoral Dacron prosthesis, whereas the other seven patients underwent replantation of the IMA into the Dacron prosthesis. All patients did well postoperatively. In the 14 general surgical patients, intestinal viability and collateral mesenteric blood flows were determined, which demonstrated that the presence of audible arterial blood flow correlated with ultimate bowel viability. We recommend the use of the Doppler ultrasonic flowmeter in abdominal aortic revascularization procedures to determine the need for IMA reconstruction as well as in general surgical procedures where the surgeon desires a more objective assessment of intestinal viability.(Arch Surg 114:165-168, 1979)

Preservation of autologous blood during cardiac surgery may reduce the need for homologous blood transfusions. We reviewed our experience for patients undergoing primary coronary revascularization to determine the effect of the use of the Haemonetics Cell-Saver upon blood bank resources and upon the cost of operation.The quantity of homologous blood required by two groups of patients was compared. One group of 46 patients had operation prior to use of the Cell- Saver ; the other group of 31 patients was entered into Cell-Saver protocols. The mean number of homologous blood units transfused per patient fell strikingly (p < 0.0001) from 4.2 before to 0.5 after introduction of the Cell- Saver. Of the 31 patients in the Cell-Saver protocol, 71 % required no homologous blood while they received 2.5 units of autologous blood processed by the Cell-Saver. Related to this, the mean number of units prepared by typing and compatibility testing in anticipation of surgery fell from 10 units to five. The projected cost to the patient fell 23%. There were no adverse effects from the use of the Cell-Saver.We conclude that the use of the Cell-Saver is justified not only to reduce the potential risks of homologous blood transfusion, but also to reduce the strain upon blood bank resources and the patient cost of primary coronary revascularization.

Internal carotid artery (ICA) back pressure correlates collateral cerebral blood flow, providing a critical pressure necessary for carotid endarterectomy without a shunt. The ICA back pressures were measured in 43 patients undergoing 50 endarterectomies under regional anesthesia. A four-minute ICA test occlusion was used to determine need for shunting. Mean ICA back pressure was 69 ± 2 (SE) mm Hg in 22 procedures (group 1), 34 ± 2 mm Hg in 25 procedures (group 2), and 15 ± 3 mm Hg in three procedures (group 3). Differences between groups were significant (P &lt;.05) without significant (P>.05) differences in systemic pressure. Group 3 patients did not tolerate temporary carotid occlusion, confirming 25 mm Hg as the lower limit of adequate collateral flow. Five patients developed neurological complications, three in group 1 and two in group 2. Embolization may have occurred in two patients. However, some patients require more than minimum collateral flow and consequently need ICA back pressures higher than 25 to 50 mm Hg.

The physiological significance of coronary obstructions of intermediate severity are difficult to assess from the angiogram alone. The hemodynamic significance of clinical coronary stenoses can be readily assessed, however, with a miniaturized Doppler probe developed at The University of Iowa Hospitals and Clinics to measure phasic coronary velocity. No dissection of the coronary vessel is required. The probe is held in place over the coronary vessel with a small suction cup. Reactive hyperemia responses obtained following a 20 second occlusion clearly demonstrate the hemodynamic significance of a coronary stenosis. We have employed this approach in 64 patients with coronary artery disease. In 12 (19%) in whom the degree of stenosis of the vessel was equivocal (diameter narrowing 25% to 70%), the use of the Doppler probe and a 20 second reactive hyperemia curve allowed accurate and immediate assessment of the need for a bypass. Five of these equivocal lesions did not produce any alterations in coronary reserve and, accordingly, the vessels were not bypassed. In seven of them, the reactive hyperemia response was markedly depressed and as a result the vessel in question was bypassed. Thus measurements of coronary reactive hyperemia in vessels with obstruction of intermediate severity can influence the operative plan by assessing the physiological significance of the obstruction.

It has been reported that the cyclic dopamine analog 5,6-dihydroxy-2-methylaminotetralin (M-8) is an adrenergic agonist in the dog. In this study, the effects of M-8 on hindlimb vascular responses were determined in the dog. In group I (n= 10), hindlimb vascular responses to ipsilateral femoral artery injections of M-8 before and after adrenergic blockade were determined. Mean femoral artery and peripheral venous pressures and heart rate responses to intra-arterial injections of M-8 were recorded. Mean femoral artery flows were measured by an electromagnetic flowmeter. Low doses of M-8 (0.0001–0.1 μg/kg) elicited transient dilatory responses, while higher doses (1–10 μg/kg) produced a biphasic response consisting of a dilation followed by constriction. The dilatory responses were attenuated following pre-treatment with propranolol and were augmented by pretreatment with phenoxybenzamine. The constrictor responses were attenuated by pretreatment with phenoxybenzamine and augmented by pretreatment with propranolol. These responses were not reflex-mediated, since the hemodynamic parameters in the contralateral limb were not altered during the depressor or pressor phases. In group II (n= 5), the effects of intra-arterially infused M-8 (0.01 μg/kg/min) on plethysmographically determined hindlimb venous capacitance were determined. Intra-arterial infusion increased venous capacitance through β-adrenergic mechanisms without altering mean arterial pressure and heart rate or contralateral limb mean femoral artery flows. M-8 is a potent peripherally acting adrenergic agent.

The optimal solution for priming cardiopulmonary bypass machines and for postoperative resuscitation following myocardial revascularisation should be inexpensive, free of risk of transmitting disease, and free of other detrimental side effects. Colloid solutions are preferred over crystalloid solutions because of elevations in extracellular sodium and water that occur with cardiopulmonary bypass.

An equation of mechanical energy balance in a liquid jet atomizing in an ambient gas is derived. The time rate of change of kinetic energy of the fluctuating disturbance in a given volume of the jet is shown to be equal to the sum of four types of works done per unit time on the jet and the energy dissipation rate through the agent of viscosity. The four types of works involved are the work by the surface tension, the work by the pressure fluctuation in the ambient gas, the work done by the fluctuating pressure in the jet, and the work by the viscous stress. Numerical results obtained for a wide range of relevant parameters are used to show that the surface tension work is negative in jet atomization. This is contrary to the situation in the breakup of an ink jet for which the surface tension work is positive, and thus the breakup is due to capillary pinching. It is shown that the work by fluctuating gas pressure is responsible for the atomization process, since the pressure work term is the dominant positive term in the energy budget of the jet atomization.

From November, 1980, to May, 1985, 699 patients have undergone percutaneous transluminal coronary angioplasty of 784 lesions at our institutions. Simultaneous surgical standby was available on all cases. One hundred twenty-four patients (18%) underwent immediate myocardial revascularization; 45 (6%) were operated on because the lesion could not be dilated. Seventy-nine patients (11%) underwent immediate operation for an acute complication of angioplasty: coronary occlusion in 45, dissection in 29, coronary perforation in three, and atrial perforation in one. Fourteen patients (18%) required cardiopulmonary resuscitation en route to the operating room, and 10 patients (20%) had insertion of an intra-aortic balloon pump in the cardiac catheterization laboratory. The average time from complication to reperfusion was 87 minutes, ranging from 40 to 165 minutes. An average of 2.0 grafts per patient (ranging from one to five grafts per patient) were performed. Of those 79 patients who underwent operation for an acute complication, one died (1.3%), 31 patients (39%) had a myocardial infarction according to enzyme criteria (creatine kinase-myocardial band greater than 40 IU), and 17 patients (22%) had new Q waves on the electrocardiogram. Good results are related to minimizing the time the myocardium is ischemic. No patient in whom reperfusion was begun in less than 75 minutes had a Q wave infarction or a creatine kinase–myocardial band level greater than 40 IU. Simultaneous surgical standby is the only method allowing immediate access to surgical facilities. A standby team of eight persons and equipment were immediately available for emergency bypass grafting for an average of 3.6 hours (range 1.3 to 5.4 hours per angioplasty attempt). The patient charges for this simultaneous standby were $632.00 per angioplasty attempt, or $442,278.00 for the entire series. The actual cost of the standby was over $1,700.00 per attempt totaling $1,188,843.00 for the 699 patients. This underestimation of the cost of surgical standby has occurred in other series, because little mention has been made of this cost in the published reports on the cost effectiveness of angioplasty. In terms of time demands, over 2,500 hours were spent by surgeons standing by for the 699 attempts. Simultaneous surgical standby is the most effective means of limiting the time the myocardium is ischemic after an angioplasty complication. However, this method is costly, necessitating more of a financial and time commitment than generally anticipated. Future studies of the cost effectiveness of angioplasty should include the cost of surgical standby with accurate per-patient cost accountability.

• Measurement of Doppler segmental arterial pressures in the lower extremity using narrow pneumatic cuffs has become a standard noninvasive diagnostic technique. Correlation between arteriographic and noninvasive studies was available for 345 aortoiliac segments and 326 femoropopliteal segments. If stenoses of 50% or greater and occlusions were considered hemodynamically significant, the sensitivity to aortoiliac disease was 97%, but only 67% to femoropopliteal disease. The specificity for hemodynamically insignificant disease was 50% and 68%, respectively. Accuracy was influenced by the presence of associated aortoiliac or femoropopliteal disease. The sensitivity to hemodynamically significant femoropopliteal disease was 55% if there was associated aortoiliac disease, and 89% in its absence. In the presence of significant femoropopliteal disease, specificity for the absence of aortoiliac disease decreased from 70% to 41%.(Arch Surg 1984;119:465-467)

• One hundred fifteen patients over 65 years of age were operated on at our institution for coronary artery bypass grafting (CABG). The operative mortality was 5% compared with an overall operative mortality of 2.5% in the last five years for 1,500 persons with CABG. Increased risk factors included qualification for New York Heart Association (NYHA) class IV, ejection fraction of less than 35%, diffuse disease requiring more than five grafts, and age over 75 years. At one year after operation, 81% of the patients were clinically improved, and the survival rate was 91%. Patients over 65 years of age in NYHA classes II and III with good left ventricular function requiring four or less bypass grafts appeared to have an excellent prognosis both acutely and during a one-year follow-up period.(Arch Surg 1983;118:402-404)

It has previously been shown that albumin costs in a Veterans Administration Hospital constituted a large portion of the pharmacy drug budget and that much albumin was prescribed inappropriately. Therefore, a program of education and use monitoring was instituted to improve understanding and prescribing of this product. Inappropriate use declined from 41% to 26% of total albumin units and, more dramatically, total cost of albumin used had decreased by 90% one year after this program was initiated. Projected yearly savings from decreased use was more than $85,000. These results demonstrate that such a program can promote more appropriate use of albumin and effect a cost savings for hospitals.(JAMA 1982;247:831-833)

• Colonic serosal and mesenteric blood flows were assessed by use of the Doppler ultrasound device during three colon bypass procedures for obstructing esophageal carcinoma. The technique allowed confirmation of pulsatile blood flow in large and small vessels after mobilization of the colon and following completion of critical anastomoses. We recommend use of this technique to eliminate serious compromise of colonic blood flow in colon bypass procedures.(Arch Surg 112:270-272, 1977)

Convulsions have not been emphasized as a possible complication of carotid endarterectomy. We describe here three patients in whom seizures with a focal component developed postoperatively. We suspect that the convulsions were secondary to a cerebral embolus arising from the operative site. An unstable preoperative neurological status is not a prerequisite for this complication.(JAMA 244:1827-1828, 1980)

<$O_ST_ABS>AUTHORS SYNOPSIS<$C_ST_ABS>Intra-arterial injection of oral and parenteral forms of several classes of drugs of abuse have been studied. The peripheral vascular insufficiency following the administration of these drugs does not appear to be a result of vasospasm. In the present study significant crystal formation and platelet aggregation did not occur. Additional parameters and mechanisms must be examined to clarify the aetiology and therapy for this syndrome.