William G. Lindsay

Ten years' experience with the St. Jude Medical valve prosthesis

Records of 1,298 consecutive patients who had received the St. Jude Medical prosthesis were reviewed (713 male and 585 female patients; mean age, 61.79 +/- 13.4 years). Early mortality was 5.7% (74 patients). Ninety-three percent complete follow-up was accomplished for the 1,224 patients who left the hospital (4,306.50 patient-years). One hundred ninety-two of these patients died, a late mortality of 16.9%. Sixty-four patients experienced thromboembolic episodes (17 major and 35 permanent). Twenty-four patients had anticoagulant-related bleeding, 4 had valve thrombosis, 7 had prosthetic valve endocarditis, 9 had paravalvular leak, and 10 underwent reoperation. There was no structural valve failure in this series. Twenty-two of the 118 patients who had valve-related complications died; another 15 patients died of sudden and unknown causes. Therefore, the total number of valve-related deaths was 37. Of those patients who survived, New York Heart Association functional class improved significantly (98% in classes II and III preoperatively and 96% in classes I and II postoperatively). Linearized rates for thromboembolism, valve thrombosis, and anticoagulant-related bleeding were 1.49% +/- 0.19%, 0.09% +/- 0.05%, and 0.56% +/- 0.11%/100 patient-years, respectively. The actuarial estimate of incidence free from all complications, operative death, and valve-related death was 66.9% +/- 8.2% at the end of 9 years. In spite of old age and advanced heart disease, the patients who received the St. Jude Medical prosthesis had very good results over a 10-year period.

Influence of Aspirin and Dipyridamole on Patency of Coronary Artery Bypass Grafts

A prospective randomized trial was performed to determine if the administration of inhibitors of platelet function would improve the patency of coronary artery bypass grafts. Patients were operated on for intractable angina with angiographically demonstrable lesions. The left internal mammary artery (IMA) was used for bypass of lesions of the left anterior descending coronary artery (LAD). Saphenous vein grafts were used for the LAD if the IMA was inadequate and for all other vessels. Treated patients received 1,300 mg of aspirin and 100 mg of dipyridamole (Persantine) orally each day. Control patients received neither drug. Patients returned 3 to 6 months after operation for repeat angiography. Results were analyzed by chi-square. One hundred seventy-four patients entered the study from June, 1973, through December, 1975, and 113 were analyzed. In the control group, 66 patients had 27 IMA-LAD grafts and 93 saphenous vein grafts. In the treatment group, 47 patients underwent 18 IMA-LAD grafts and 75 saphenous vein grafts. Ninety-eight of the 120 grafts (82%) were patent in the control group, and 87 of 93 grafts (94%) were patent in the treatment group (x2 = 6.34, p less than 0.02). Of the 45 IMA-LAD grafts in both groups, only 1 was occluded, a patency of 98%. In the control group, 72 of 93 saphenous vein grafts (77%) were patent. In the treatment group, 69 of 75 (92%) were patent (x2 = 6.54, p less than 0.02). The results of the study show a 15% difference between the two groups in the early patency of saphenous vein grafts. We continue to use aspirin and dipyridamole to improve the patency of saphenous vein bypass grafts.

St. Jude Medical Prosthesis: Valve-Related Deaths and Complications

Despite the hemodynamic improvement in cardiac valve prostheses, valve-related deaths and complications have remained a substantial source of morbidity and mortality. This follow-up study was carried out in April, 1986, in a group of 816 patients who received 876 St. Jude Medical prostheses between October, 1977, and October, 1984. One hundred fifty-five patients (37%) of the 422 having aortic valve replacement (AVR) and 88 (29%) of the 300 having mitral valve replacement (MVR) had concomitant coronary artery bypass grafting, and 94 patients (12%) had miscellaneous procedures performed in addition to valve replacement. Sixty-three patients died within the operative period, an operative mortality of 7.7%. Follow-up was complete for 98% of the patients; the mean follow-up was 42 months. At that time, 87 more patients had died, a late mortality of 11.9%. There were 13 valve-related deaths (4 in the AVR group, 7 in the MVR group, and 2 in the miscellaneous group); the causes of death were thromboembolism (7), anticoagulant-related hemorrhage (2), valve thrombosis (2), prosthetic valve endocarditis (1), and perivalvular leak (1). There were 37 thromboembolic episodes (1.78/100 patient-years) and 67 anticoagulant-related hemorrhages (3.22/100 patient-years), 46% of which necessitated transfusion. The incidence of valve thrombosis was 0.6% (4 patients). Perivalvular leak and prosthetic valve endocarditis occurred in 7 patients (1.0%) and 5 patients (0.7%), respectively. Reoperation was carried out in 6 patients (0.8%), but only for perivalvular leak. There were no deaths, no complications, and no clinical evidence of malfunction of the prosthetic valve.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of cardiopulmonary bypass on cefazolin disposition

Cefazolin kinetics was studied in 8 patients the day before (PREOP), during (SURG), and the day after (POSTOP) cardiopulmonary bypass (CPB) surgery. PREOP (48.6 ml/min) and POSTOP (46.6 ml/min) total body clearances were of the same order and both were greater than the SURG (27.4 ml/min) total body clearance. Since cefazolin is almost entirely eliminated by the kidney, the lower SURG clearance is a result of reduced renal elimination, as confirmed by measuring cefazolin SURG (28.7 ml/min) and POSTOP (52.9 ml/min) renal clearance. The reduction in cefazolin renal elimination was the same throughout the surgical procedure, including the period of extracorporeal circulation. Cefazolin distribution was altered by the operative procedure as evidenced by a higher SURG steady‐state volume of distribution. This increase in apparent cefazolin distribution volume brought about by surgery was not seen with cephalothin, which was investigated by us in a similar group of patients. The different effect of CPB surgery on cefazolin and cephalothin distribution may be due to differences in plasma protein binding.

Cephalothin kinetics: Before, during, and after cardiopulmonary bypass surgery

Cephalothin kinetics was studied in 5 patients the day before (PREOP), during (SURG), and the day after (POSTOP) cardiopulmonary bypass surgery. The PREOP (114 ml/min) and SURG (94 ml/min) renal clearances were of the same order but both were less than POSTOP renal clearance (248 ml/min). Cephalothin total body clearance during operation was lower (p < 0.01) than PREOP or POSTOP clearance, with decreased metabolic clearance the primary cause. There was reduction in cephalothin elimination throughout the surgical procedure, not only in the period of extracorporeal circulation, indicating that general anesthesia had a significant influence on drug disposition. The metabolite deacetylcephalothin was rapidly formed on all 3 days and its kinetic behavior paralleled that of the parent drug.

Hemodynamic Evaluation of Lillehei-Kaster and Starr-Edwards Prostheses

The central-flow low profile disc-valve prosthesis has been offered as an alternative to ball- and tissue-valve prostheses. Extensive laboratory investigation with both pulse duplicator and experimental animals has been reported for the Lillehei-Kaster prosthesis. A series of patients receiving this prosthesis underwent postoperative cardiac catheterization to better define the hemodynamic function of this prosthesis in vivo. Because of the variations in reports of hemodynamic data from various institutions, the results of post-operative studies in an earlier group of patients with Starr-Edwards prostheses were used as a standard for comparison. Good hemodynamic function was found with the pivoting-disc prosthesis in all but the smallest valve sizes. Lillehei-Kaster and early model Starr-Edwards prostheses with equivalent tissue annulus dimensions were found to have nearly equal valve areas in vivo in the aortic position. The Lillehei-Kaster mitral valves provided larger areas than Starr-Edwards prostheses in large tissue annulus sizes.

The influence of prophylactic antibiotics on the warfarin anticoagulation response in the postoperative prosthetic cardiac valve patient. Cefamandole versus vancomycin.

The influence of cefamandole and vancomycin used for prophylaxis on the warfarin anticoagulation response in 60 cardiac valve replacement patients during the postoperative period is presented. Patients were divided into two groups, hyper-responders prothrombin time (PT) greater than or equal to 32 sec, 48 hr after the initial warfarin dose (GrIHR), or normal responders PT less than 32 sec (GrIINR). Fifteen patients (25%) were in GrIHR (PT 44.3 +/- 10.5) and 45 in GrIINR (21 +/- 5). Fourteen of the 15 GrIHR patients received cefamandole and 1 of the 15 GrIHR patients received vancomycin p less than 0.05, as prophylaxis. Warfarin sensitivity was assessed using a warfarin dose index (WDI) calculated in the initial postoperative period (WDIINT) and at discharge (WDIDIS). GrIHR patients had greater WDIINT and WDIDIS compared to GrIINR p less than 0.001. Baseline prothrombin time measured 8 hours prior to start of warfarin therapy (PTBL), was linearly correlated to the WDIINT with r = 0.8, p less than 0.001 in cefamandole patients only. The data suggests that cefamandole increases warfarin sensitivity early in the postoperative course of oral anticoagulation therapy, which may lead to excessively high prothrombin times with the possibility for serious bleeding.

Free-Water Clearance and the Early Recognition of Acute Renal Insufficiency after Cardiopulmonary Bypass

The predictive value of free-water clearance measurements for the early recognition of acute renal insufficiency was evaluated in 59 patients immediately following cardiopulmonary bypass. Blood urea nitrogen and serum creatinine measurements were taken before and after operation. Intraoperatively, immediately after completion of bypass, urine and serum samples were obtained for osmolality. Duration of bypass, urine output, degree of hemolysis, and quality of perfusion were recorded. Fifty-four patients developed no signs of renal insufficiency following bypass, and all had free-water clearance values equal to or less than -20 ml per hour. Five patients who had free-water clearance values equal to greater than -8 ml per hour developed manifestations of an acute renal insufficiency state. There were no false-negative or false-positive determinations. Consequently, free-water clearance measurements appear to be a reliable indicator of those patients who will develop renal insufficiency following cardiopulmonary bypass. Early recognition provides an opportunity immediately after operation for initiating treatment consisting of administration of diuretics, potassium restriction, and oliguric fluid regimens.

The comparative influence of prophylactic antibiotics on the prothrombin response to warfarin in the postoperative prosthetic cardiac valve patient: cefamandole, cefazolin, vancomycin

A prospective randomized trial was conducted comparing the effect of three antibiotics: cefamandole (CM), cefazolin (CZ), and vancomycin (V), used as prophylaxis for prosthetic valve surgery, on the prothrombin (FT) response to warfarin (W) on the third day of anticoagulant therapy. Twenty patients, with normal preoperative PTs, were randomized to each antibiotic. Their PTs were not significantly different at 2 hours after operation and the morning before W was begun. The three groups received similar W doses for 2 days, and the PT, as percentage of activity, on the morning of the third day demonstrated that V (51 ± 18%) was significantly greater (p < 0.005) than CM (29 ± 14%) or CZ (38 ± 18%). CM had a significantly greater percentage of change in PT (64 ± 14%, p < 0.0001) from the first to third day than either CZ (51.1 ± 18%) or V (44. 6 ± 19%). CM also had a greater number of patients (6) with PTs ≥ 30 seconds on day 3 than either CZ (1) or V (1). The antibiotic influence on the PT response to W in this study is ranked as CM > CZ > V.

Chronic Granulomatous Disease of Childhood : Surgical Considerations

Abstract Experience with 25 cases of chronic granulomatous disease of childhood seen at the University of Minnesota Hospitals is reviewed. A unique combination of granulomatous, suppurative disease is commonly encountered in lymph nodes, lung, liver, bones, skin, and other parenchymatous organs. Early definitive excisional drainage or extirpation of the involved organ has proved successful in the control of infection in these patients and the concept of en bloc resection of all infected tissue is presented. The unique combination of granuloma formation and suppuration that coexists in areas of infection in these children seems to justify this approach to therapy that is unresponsive to conventional antibiotics.