Citations

Background Although an inverse relation between physician caseload and complications has been conclusively demonstrated for several surgical procedures, such data are lacking for percutaneous coronary intervention, and the ACC/AHA guidelines requiring ≥75 cases per year for operator “competency” are considered by some physicians to be arbitrary. Methods and Results From quality-controlled databases at five high-volume centers, models predictive of death and the composite outcome of death, Q-wave infarction, or emergency bypass surgery were developed from 12 985 consecutively treated patients during 1993 through 1994. Models had moderate to high discriminative capacity (area under ROC curves, 0.65 to 0.85), were well calibrated, and were not overfitted by standard tests. These models were used for risk adjustment, and the relations between both yearly caseload and years of interventional experience and the two adverse outcome measures were explored for all 38 physicians with ≥30 cases per year. The average physician performed a mean±SD of 163±24 cases per year and had been practicing angioplasty for 8±5 years. Risk-adjusted measures of both death and the composite adverse outcome were inversely related to the number of cases each operator performed annually but bore no relation to total years of experience. Both adverse outcomes were more closely related to the logarithm of caseload (for death, r =.37, P =.01; for death, Q-wave infarction, or bypass surgery, r =.58, P <.001) than to linear caseload. Conclusions In this analysis, high-volume operators had a lower incidence of major complications than did lower-volume operators, but the difference was not consistent for all operators. If these data are validated, their implications for hospital, physician, and payer policy will require exploration.

Background With the thrombogenic tendency and permanent implant nature of metallic stents, synthetic polymers have been proposed as candidate materials for stents and local drug delivery designs. We investigated the biocompatibility of several synthetic polymers after experimental placement in the coronary artery. Methods and Results Five different biodegradable polymers (polyglycolic acid/polylactic acid [PGLA], polycaprolactone [PCL], polyhydroxybutyrate valerate [PHBV], polyorthoester [POE], and polyethyleneoxide/polybutylene terephthalate [PEO/PBTP]) and three nonbiodegradable polymers (polyurethane [PUR], silicone [SIL], and polyethylene terephthalate [PETP]) were tested as strips deployed longitudinally across 90° of the circumferential surface of coil wire stents. Appropriately sized polymer-loaded stents were implanted in porcine coronary arteries of 2.5- to 3.0-mm diameter. Four weeks after implantation, stent patency was assessed by angiography followed by microscopic examination of the coronary arteries. The biodegradable PCL, PHBV, and POE and the nonbiodegradable PUR and SIL evoked extensive inflammatory responses and fibrocellular proliferation (thickness of tissue response: 0.79±0.22, 1.12±0.01, 2.36±0.60, 1.24±0.36, and 1.43±0.15 mm, respectively). Less but still severe responses were observed for the biodegradable PGLA and PEO/PBTP (0.46±0.18 and 0.61±0.23 mm, respectively) and for the nonbiodegradable PETP (0.46±0.11 mm). Conclusions An array of both biodegradable and nonbiodegradable polymers has been demonstrated to induce a marked inflammatory reaction within the coronary artery with subsequent neointimal thickening, which was not expected on the basis of in vitro tests. The observed tissue response may be attributable to a combination of parent polymer compound, biodegradation products, and possibly implant geometry.

Of the 614 open-heart operations performed at the Mayo Clinic for acquired aortic valvular disease, 130 were performed on patients who also required repair of other valves. Review of the remaining 484 operations resulted in the following observations. Operation for acquired aortic valvular disease may now be accomplished with a hospital mortality rate of 4%. The incidence of late death and failure of patients to improve has averaged 44% for previously employed techniques of valvular repair. Failure of the valve or prosthesis to function properly was the most common cause of late failure after operations in which these earlier methods were used. In the 138 more recent cases, in which operations employing the aortic ball valve (Starr-Edwards prosthesis) were used, the incidence of late failure has been reduced to 14%, and failure of the prosthesis to function properly has not yet occurred in the absence of infection. Late bacterial endocarditis and thromboembolism were the most serious problems associated with use of the ball-valve prosthesis. In contrast with the late results of the former techniques, use of the ball valve has resulted in improvement for 79% of the patients; in the great majority of these there has been a dramatic return to normal living. Despite the highly satisfactory results of current methods, the fact that 14% of patients have already died after an initially successful operative result, and that another 12% have suffered complications causing their late result to be less than totally satisfactory, indicates that the policy of recommending for operation only those patients who have significant and progressive cardiac disability should be continued.

Recently we have studied the role of surgical treatment of patients having occlusive cerebrovascular disease, particularly incipient stroke (or focal intermittent cerebrovascular insufficiency). This report concerns 35 pa-patients with incipient stroke in whom circulation was restored to normal by operation on an artery in an attempt to prevent transient ischemic episodes and cerebral infarction. Since all of the patients were neurologically normal at the time of the surgical procedure, we were concerned primarily with the risk of [see tablein the PDF file] the procedure, particularly in terms of cerebral infarction. The operative mortality rate was 8.5 per cent (three patients). Six patients (17 per cent) sustained cerebral infarcts. Four of these had mild neurologic deficits, usually consisting of clumsiness and mildly reduced discriminatory sensation in one hand; one had a severe neurologic deficit, and one died. Evidence shows that at least some of these infarcts resulted from emboli arising from the operative site at the time of or shortly after the operation. The results of long-term follow-up revealed that 66 per cent of the surgically treated patients were normal compared to 25 per cent of a contrast group; and 17 per cent of the treated patients had suffered cerebral infarcts compared to 40 per cent of the contrast group. The long-term results are thus similar to the immediate postoperative results. These findings simply indicate that an operated patient's prognosis was good over the long term if the cerebral ischemic episodes were relieved and if he sustained no complications from the surgical procedure.

Nineteen patients with ventricular septal defect and severe aortic valvular incompetence have been operated on at the Mayo Clinic. There were two early deaths and two late deaths. The ventricular septal defect was located high and anteriorly in the septum and was often small. Aortic valvular incompetence was due, in most cases, to a deformed, prolapsing right coronary cusp. Mild to moderate degrees of infundibular pulmonary stenosis coexisted in nine patients. Repair of the ventricular septal defect was readily accomplished in most cases by direct suture, and relief of obstruction to right ventricular outflow was effected, when required, by resection of the crista supraventricularis. Repair of the aortic incompetence was attempted by a variety of means, but the incidence of persistent significant regurgitation was high, except when prosthetic cusp replacement was used. It is currently our policy to defer operation in children unless there are significant symptoms. When the patient is past the age of about 12 to 14 years, operation is advised under proper circumstances, and it consists generally of suturing of the ventricular septal defect and replacement of the right coronary cusp of the aortic valve.

Open operation by means of extracorporeal circulation has been used on 47 patients with congenital aortic stenosis at the Mayo Clinic between April 1955 and July 1, 1960; 33 patients had valvular stenosis, 11 had subvalvular stenosis, and three had supravalvular stenosis. The over-all operative mortality rate was 13 per cent; 6 per cent of patients with valvular aortic stenosis died in the hospital. Severe aortic insufficiency did not develop in any patient operated on for valvular aortic stenosis although a diastolic murmur was present after operation in some. Rarely, however, was the transvalvular gradient completely eliminated by operation although 90 per cent of the surviving patients were either asymptomatic or had definite clinical improvement. Late follow-up hemodynamic studies suggest that a persistent transvalvular gradient may regress in time. Relief of obstruction caused by subvalvular variety of aortic stenosis is difficult whether stenosis is localized or diffuse. Even in this gruop, however, it has been possible to achieve good results with careful attention to certain technical details. Patients with congenital aortic stenosis should be operated on before the development of the sequelae of severe left ventricular hypertension.

Arteriovenous fistula involving the portal vein or its tributaries is a rare condition that in some cases can be treated successfully by surgery if it is recognized. The clinical manifestations and diagnostic criteria are presented.

Obstruction to pulmonary blood flow may occur in the pulmonic valve, in the infundibulum or in both. Cardiac catheterization aids in the determination of the site of obstruction. Criteria for the differentiation at operation of valvular and infundibular pulmonic stenosis are enumerated, and the usefulness of accurate pressure tracings during operation is emphasized. The accurate identification of the site or sites of obstruction to pulmonary blood flow is essential to proper surgical management. A correctly selected operation must be carried out in as complete a manner as possible.