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Coronary angioplasty has been increasingly utilized in patients with extensive coronary disease, severe and acute chest pain syndromes, and poor ventricular function. This process has been facilitated in part by use of circulatory support, including perfusion balloons, intraaortic balloon pumps and cardiopulmonary bypass support systems. Percutaneous cannulation has facilitated elective and emergency application of cardiopulmonary bypass support in patients undergoing high risk coronary angioplasty. A National Registry of 25 centers has accumulated data on 801 elective and 210 emergency support angioplasty patients. Standby cardiopulmonary bypass support of elective high risk patients was associated with fewer complications and less in-hospital mortality in patients other than those with left ventricular ejection fraction < or = 20% and possibly older high risk patients. In elective cases, circulatory support was required in only approximately 7% of high risk patients, although need appeared to be unpredictable. Emergency use of cardiopulmonary bypass support, initiated < 20 minutes from the time of circulatory collapse, was associated with improved patient prognosis. Overall, patients undergoing circulatory cardiopulmonary bypass supported angioplasty had a marked reduction in anginal status, improvement in left ventricular ejection fraction and good (80%) 2-year survival. Although used only occasionally, circulatory support remains an important prophylactic interventional tool for the extremely high risk patient (left ventricular ejection fraction < or = 20%) and a lifesaving emergency technique for the occasional patient with circulatory collapse.

The National Registry of Supported Angioplasty was formed in 1988 to collect data on patients undergoing supported angioplasty. The Registry was expanded to include patients also undergoing standby supported angioplasty. In 3 years the Registry collected data on 801 patients undergoing supported or standby supported angioplasty. The data indicate that in patients with low ejection fractions and/or > or = 50% of jeopardized myocardium at risk can have an interventional procedure performed with a 6.9% risk of mortality with prophylactic or standby support, but patients with < or = 20% ejection fraction do better with prophylactic support. In addition, patients with LMCA stenosis and age > or = 70 years are at higher risk. The Registry also demonstrates good long-term results for patients who have undergone the procedure.

Objectives: Data from a national registry of 23 centers using cardiopulmonary support (CPS) were analyzed to compare the risks and benefits of prophylactic CPS versus standby CPS for patients undergoing high risk coronary angioplasty., Background: Early data from the CPS registry documented a high angioplasty success rate as well as a high procedural morbidity rate. Because of this increased morbidity some high risk patients were placed on standby CPS instead of prophylactic CPS., Methods: Patients in the prophylactic CPS group had 18F or 20F venous and arterial cannulas inserted and cardiopulmonary bypass initiated. Patients in the standby CPS group were prepared for institution of cardiopulmonary bypass, but bypass was not actually initiated unless the patient sustained irreversible hemodynamic compromise., Results: There were 389 patients in the prophylactic CPS group and 180 in the standby CPS group. The groups were comparable with respect to most baseline characteristics, except that left ventricular ejection fraction was lower in the prophylactic CPS group. Thirteen of the 180 patients in the standby CPS group sustained irreversible hemodynamic compromise during the angioplasty procedure. Emergency institution of CPS was successfully initiated in 12 of these 13 patients in < 5 min. Procedural success was 88.7% for the prophylactic and 84.4% for the standby CPS group (p = NS). Major complications did not differ between groups. However, 42% of patients in the prophylactic CPS group sustained femoral access site complications or required blood transfusions, compared with only 11.7% of patients in the standby CPS group (p < 0.01). Among patients with an ejection fraction < or = 20%, procedural morbidity remained significantly higher in the prophylactic CPS group (41% vs. 9.4%, p < 0.01), but procedural mortality was higher in the standby group (4.8% vs. 18.8%, p < 0.05)., Conclusions: Patients in the standby and prophylactic CPS groups had comparable success and major complication rates, but procedural morbidity was higher in the prophylactic group. When required, standby CPS established immediate hemodynamic support during most angioplasty complications. For most patients, standby CPS was preferable to prophylactic CPS during high risk coronary angioplasty. However, patients with extremely depressed left ventricular function (ejection fraction < 20%) may benefit from institution of prophylactic CPS.

To assess the outcome of PTCA in circulatory supported patients with left main coronary artery (LMCA) stenosis, the National Registry of Elective Supported Angioplasty data bank was searched. Patients entered in the registry were considered high-risk PTCA and the PTCA was performed using percutaneous cardiopulmonary bypass (PCPB). Criteria for high risk was left ventricular ejection fraction less than or equal to 25% or a target lesion supplying greater than or equal to 50% of functioning myocardium. Of 455 patients entered in the registry, 61 (13.3%) had LMCA stenosis greater than or equal to 60%. There were 42 patients in whom the PTCA target vessel was the LMCA (PTCA-LMCA) and 19 in whom it was vessel(s) other than the LMCA (PTCA-OTHER). The mean age was similar in the 2 groups (65 +/- 10 vs. 68 +/- 9 yrs, p = ns). The left ventricular ejection fraction (LVEF) was higher in PTCA-LMCA than in PTCA-other (38 +/- 16% vs. 27 +/- 16%, p less than 0.05). The number of vessels dilated/patient was higher in PTCA-LMCA than in PTCA-OTHER (2.1 +/- 1.0 vs. 1.1 +/- 0.3, p less than 0.001). There were a total of 10 in-hospital deaths (16%) in patients with LMCA greater than or equal to 60% stenosis. This exceeds the mortality of the patients with less than 60% LMCA stenosis entered in the registry (4.5%, p less than 0.001). There were 6 in-hospital deaths (14%) in PTCA-LMCA and 4 (21%) in PTCA-OTHER (p = ns).(ABSTRACT TRUNCATED AT 250 WORDS)

Indications for coronary angioplasty have expanded to include patients with unstable acute ischemic syndromes, severe multivessel coronary artery disease and impaired left ventricular function. Several mechanical approaches have been developed as adjuncts to high risk coronary angioplasty to improve patient tolerance of coronary balloon occlusion and maintain hemodynamic stability in the event of complications. These percutaneous techniques include intraaortic balloon counterpulsation, anterograde transcatheter coronary perfusion, coronary sinus retroperfusion, cardiopulmonary bypass, Hemopump left ventricular assistance and partial left heart bypass. The intraaortic balloon pump provides hemodynamic support and ameliorates ischemia by decreasing myocardial work; it may be inserted for periprocedural complications or before angioplasty in patients with ischemia or hypotension. Anterograde distal coronary artery perfusion may be accomplished passively through an autoperfusion catheter or by active pumping of oxygenated blood or fluorocarbons through the central lumen of an angioplasty catheter. Synchronized coronary sinus retroperfusion produces pulsatile blood flow via the cardiac veins to the coronary bed distal to a stenosis. Both perfusion techniques limit development of ischemic chest pain and myocardial dysfunction in patients undergoing prolonged balloon inflations. Percutaneous cardiopulmonary bypass provides complete systemic hemodynamic support which is independent of intrinsic cardiac function or rhythm and has been employed prophylactically in very high risk patients before coronary angioplasty or emergently for abrupt closure. These and newer support devices, while associated with significant complications, may ultimately improve the safety of coronary angioplasty and allow its application to those who would otherwise not be candidates for revascularization.

An angioplasty catheter was developed to allow measurement of absolute coronary blood flow during interventional procedures. This method uses electrical impedance changes induced by a 0.5 ml bolus of 5% dextrose solution and indicator-dilution principles. The indicator is injected through a port located just proximal to the dilating balloon and the resulting changes in blood impedance are measured by electrodes at the catheter tip. Excellent linear correlations were found between known flow in 2 to 4 mm to diameter plastic tubes and catheter measurements (r = 0.99) and between timed collection canine femoral artery flow and catheter measurements (r = 0.97). Final validation was performed in canine coronary arteries using electromagnetic flowmeter data as the standard (r = 0.94). Thus accurate clinical determination of absolute coronary blood flow can be accomplished using this relatively inexpensive and simple catheter technique.

A National Registry of 14 centers performing elective supported angioplasty was formed to collate the initial experience with high-risk patients. Suggested indications were ejection fraction less than 25% and/or target vessels supplying greater than half of the viable myocardium. The data from 105 patients were entered into the Registry during 1988. This group included 30 patients who had dilation of their only patent coronary vessel and 20 patients whose disease was deemed too severe to undergo bypass surgery. Chest pain and ECG changes were uncommonly experienced during balloon inflation. The group experienced a high angioplasty success rate (95%) with an average of 1.7 dilatations per patient. Morbidity was frequently experienced, the majority of which was associated with cannula (18-20F) placement and/or removal. The overall hospital mortality was 7.6%, although half of the deaths occurred in patients who were both over 75 years of age and had left main coronary artery stenosis. Patients under the age of 75 years without left main coronary artery stenosis experienced a hospital mortality rate of 2.6%. Symptomatic improvement occurred in 91% of the patients surviving hospitalization. During the follow-up period of 1-12 months, three patients died of cardiac complications. This multicenter experience suggests that supported angioplasty can be performed safely in high-risk patients in several high-risk subgroups with the expectation of good symptomatic improvement and short-term survival.

Relative contraindications to coronary angioplasty have been large amounts of jeopardized myocardium and poor left ventricular function. To prevent possible hemodynamic collapse after balloon occlusion or acute vessel closure in such high risk patients, a cardiopulmonary bypass system capable of providing up to 6 liters/min output was employed prophylactically. This technique, termed supported angioplasty, results in reductions of preload and afterload and allows prolonged balloon inflations in critical coronary vessels. A National Registry of 14 centers performing elective supported angioplasty was formed to collate the initial experience with high risk patients. Suggested indications were ejection fraction less than 25% or a target vessel supplying more than half the myocardium, or both. During 1988, the data from 105 patients (mean age 62 years) undergoing supported angioplasty were entered into the Registry. This group included 20 patients whose disease was deemed too severe to permit bypass surgery and 30 patients who had dilation of their only patent coronary vessel. Seventeen patients had stenosis of the left main coronary artery and 15 underwent dilation of that vessel. Chest pain and electrocardiographic changes occurred uncommonly despite prolonged balloon inflations. During the trial, there was a progressive change from cutdown insertion to percutaneous insertion of the circulatory support cannulas. The angioplasty success rate was 95% for the 105 patients, who underwent an average of 1.7 dilations per patient. Morbidity was frequent (41 patients), in most cases due to arterial, venous or nerve injury associated with cannula insertion or removal, or both.(ABSTRACT TRUNCATED AT 250 WORDS)