Hemodynamic changes following correction of severe aortic stenosis using the Cutter-Smeloff prosthesis.

Twelve patients with pure or dominant stenosis were studied before and after aortic valve replacement (Cutter-Smeloff). The changes in cardiac output and A-V O2 difference were small and insignificant, but exercise stroke volume increased from 72 to 96 ml after the surgery. The aortic peak systolic gradient was 92 +/- 29 mm Hg before and 4 +/- 9.8 mm Hg after surgery. The PA wedge pressure, taken as a measure of the LV diastolic pressure, decreased from 18 mm Hg to 12 mm Hg at rest and 30 mm Hg to 16 mm Hg on exercise. The PA pressures also decreased from 37/18 (mean, 26) to 28/11 (17) mm Hg at rest, and 61/31 (43) to 41/17 (27) mm Hg on exercise, but the PA and PA wedge pressures maintained their tendency to increase in a linear manner with oxygen consumption (Vo2) on exercise after surgery. As a result of decreased wedge pressure, the pulmonary vascular resistance also decreased significantly afterward. The adequacy of cardiac output at rest and on exercise expressed by cardiac output as the linear function of Vo2 improved toward the normal (values before operation, CO = 2.78 + 0.0069 Vo2, r = 0.84; after operation, CO = 3.80 + 0.0062 Vo2, r = 0.91). The exercise factor (delta CO/delta Vo2) or the regression coefficient, however, was similar before and after surgery. The hemodynamic result was satisfactory although some abnormalities of the left ventricular function persisted after operation.

Six year clinical study of use of the Omniscience valve prosthesis in 219 patients.

A 6 year experience of cardiac valve replacement with the Omniscience prosthesis is described. A total of 253 valves were inserted in 219 patients. The survivors were followed up for a total of 536 patient-years and for a mean of 2.8 years. The follow-up was 97.6% complete. Analyses were performed in accordance with recommended criteria regarding definitions of complications and grading thromboembolic events for severity and analysis of anticoagulant status. Results are described both in terms of actuarial and linearized rates. For the patients at risk, actuarial survival at the end of 5 years was 87.9 +/- 3.1% overall, 90.4 +/- 3.0% for single valve (aortic 88 +/- 5%, mitral 93.3 +/- 4%) replacement and 71 +/- 11% for multiple valve replacement. The actuarial rates of freedom from complications were as follows: endocarditis 95.7 +/- 1.8% (aortic 94 +/- 3.5%, mitral 100%), periprosthetic leak 98 +/- 1% (aortic 96.2 +/- 2.6%, mitral 100%), thromboembolism 95.2 +/- 2.3% (aortic 90.9 +/- 4.6%, mitral 96.7 +/- 3.3%), valve thrombosis 98.7 +/- 0.9% (aortic 100%, mitral 100%), anticoagulant-induced bleeding 90.3 +/- 2.6% and all valve-related complications 79.4 +/- 3.6% (aortic 78.8 +/- 3.6%, mitral 85.9 +/- 4.5%). The functional improvement in patients was very satisfactory and the risk of reoperation was 1.1% per patient-year. Over a 6 year time frame, the Omniscience valve has given excellent clinical performance.

Intramyocardial arteriovenous shunting of blood with nonpulsatile perfusion.

Coronary blood drains through three types of channels: the subepicardial veins, the thebesian veins, and the arteriosinusoidal vessels. In this study the changes in the blood draining through the subepicardial and thebesian veins were measured in relation to time, up to 180 minutes. Analysis of the data yielded useful information about the relatively inaccessible microcirculation in the working heart. The first group of eight dogs was subjected to pulsatile perfusion and the second to nonpulsatile perfusion. The arteriovenous oxygen difference decreased at an identical rate of 0.01 ml of oxygen per minute per 100 ml of blood in both groups. Spontaneous increase in drainage (milliliters of blood per 100 gm of myocardium per minute) occurred as follows: Subepicardial venous drainage increased at a rate of 0.34 +/- 0.03 (mean +/- SE) with pulsatile perfusion and at a rate of 0.23 +/- 0.03 with nonpulsatile perfusion; the values were significantly different (p < 0.025). Corresponding values for thebesian venous drainage were 0.08 +/- 0.01 with pulsatile perfusion and 0.06 +/- 0.01 with nonpulsatile perfusion (p < 0.05). As a result, there was a linear increase in total myocardial oxygen utilization (MVO2) with pulsatile perfusion and a decrease with nonpulsatile perfusion. The increase in drainage with nonpulsatile perfusion, therefore, may have been due predominantly to abnormal shunt activity. The difference in drainage increase may then represent nutritive flow, the absence of which led to a fall in MVO2 with nonpulsatile perfusion. There was also some evidence that the "thebesian system" may play a compensatory role during shunting. Abnormal shunting of blood may be partly responsible for the perfusion-related myocardial damage reported in the literature.

Accidental pneumatic rupture of the esophagus.

A case of accidental pneumatic rupture of the thoracic esophagus in a 6-year-old boy is reported. Early operation with transthoracic esophageal repair resulted in survival of the patient, and follow-up at 18 months has demonstrated normal esophageal function and anatomy. A search of the literature has yielded 11 similar cases.

Extended aortic bypass.

At the University of Alberta Hospital, six patients recently underwent placement of Dacron bypass grafts from the ascending aorta to the infrarenal abdominal aorta or femoral arteries for a variety of vascular problems. The operations were performed in patients with (1) multiple aortic coarctations, (2) congenital aortic arch interruption and congenital mitral stenosis, (3) recoarctation of the thoracic aorta after previous coaractation repair (two patients), (4) aortoiliac occlusive disease in a patient with multiple previous abdominal operations including an abdominal-perineal resection and left lower quadrant colostomy, and (5) idiopathic retroperitoneal fibrosis and multiple previous operations on the abdominal aorta. Surgical access was through midline sternotomy and laparotomy incisions, and groin incisions were used as required. Careful attention was paid to placing as much graft as possible in an extraperitoneal position. All patients survived the operation and had essentially uneventful postoperative courses with good results. This technique has previously been described. However, attention is drawn to it once again as an excellent means of bypassing the thoracic and abdominal aorta in selected patients with complex vascular problems.

Carcinoid tumor of the thymus associated with recurrent pericarditis.

A 49-year-old man with carcinoid tumor of the thymus presented with the clinical picture of acute pericarditis. Recurrent bouts persisted after removal of the tumor without other evidence to indicate tumor recurrence. There were no associated manifestations of an endocrine disorder.

Long-term survival after tricuspid valve replacement. Results with seven different prostheses.

The experience with tricuspid valve replacement (TVR) with seven different prostheses, alone or combined with replacement of other valves, in 73 patients (64 rheumatic and nine nonrheumatic) between 1964 and March, 1975, at the University of Alberta Hospital has been reviewed. Early and late mortality rates in rheumatic patients were 41 and 23 percent, respectively (36 percent being alive after a mean of 5.6 years), compared to 33 and 11 percent, respectively, in the nonrheumatic patients (56 percent being alive after a mean of 2 years). Of all survivors, 88 percent were functionally improved. Among the rheumatic patients: (1) 88 percent had organic tricuspid disease; (2) of the 39 patients with tricuspid insufficiency who underwent corrective mitral surgery 7 years before TVR, the tricuspid insufficiency had progressed over the 7 years; (3) the number of patients with tricuspid insufficiency had increased (39 versus 59) over the same 7 year period; (4) a high early mortality rate was encountered in those who were preoperatively in New York Heart Association (N.Y.H.A.) Class IV, or who had cardiomegaly, or pulmonary hypertension, or poor ventricular function, or organic disease, or reoperation; (5) the percentages of survivors with different prostheses were: Starr-Edwards, 31 percent; Beall-Surgitool, 14 percent; Kay-Shiley, 46 percent, Björk-Shiley, 50 percent; Lillehei-Kaster, 100 percent; Cutter-Smeloff and Wada-Cutter, nil. Among the nonrheumatic patients, two with the Cutter-Smeloff, two with the Beall-Surgitool, and one with the Lillehei-Kaster were alive after 14, 37, and 15 months, respectively. Among all survivors of TVR, late thrombus and pannus developed on both ball and disc prostheses (Starr-Edwards, two; Cutter-Smeloff, one; Lillehei-Kaster, one). These findings suggest that TVR should be performed earlier in rheumatic patients to reduce the operative mortality rate and that the Lillehei-Kaster prosthesis is probably most suitable for TVR.

Surgical treatment of Ebstein's anomaly.

Neither the role of surgery in Ebstein's anaomaly nor the surgical procedure of choice for its correction are clearly defined. Whether or not the artrialized right ventricle, which plays a major role in the functional abnormalities, should be obliterated in all cases remains unresolved. Of the 26 patients with Ebstein's anomaly seen at the University Hospital between 1953 and 1975, four were treated surgically at this center. All had closure of the atrial septal defect, reconstruction of a tricuspid annulus in the normal position, and insertion of a tricuspid prosthesis and an epicardial ventricular pacemaker. The two patients who also had the atrialized chamber obliterated improved dramatically. Thus, obliteration of the atrialized right ventricle appears to be associated with a better operative result.

Melanotic malignant schwannoma of the right atrium.

A melanotic malignant schwannoma of the right atrium occurring in a 14-year-old girl is described. No previous such tumors in this location have been reported.

Experience with the radial artery graft for coronary artery bypass.

Forty-eight radial artery grafts and 22 saphenous vein grafts in 37 patients undergoing coronary bypass procedures were studied early postoperatively. Most of the saphenous vein grafts were patent, but one-half of the radial artery grafts were occluded. Failure of the radial artery grafts could not be attributed to unfavorable runoff in the recipient vessels. Radial arteries carrying higher flows and those to vessels having more severe degrees of proximal stenosis occluded with a higher frequency. The radial artery should not be used for coronary bypass.

Hypothermic coronary perfusion for intraoperative cardioplegia.

Hypothermic asanguineous perfusion has been used to arrest 170 hearts at the beginning of 1/2 to 2 hours of intraoperative coronary ischemia. This method of producing cardioplegia has facilitated valve replacement and coronary artery bypass operations. Inadequate myocardial protection has not been experienced since we began using this method of arresting the heart for cardiac operations.

Antimicrobial prophylaxis for open heart operations.

Between 1986 and 1988, 450 adults undergoing coronary artery bypass, cardiac valve replacement, or both were enrolled into a prospective, randomized, comparative trial of cephalothin versus cefamandole as perioperative prophylaxis. They were assessed during their hospitalization and at 6 weeks and 6 months after discharge for postoperative infectious complications. Eleven patients had major postoperative infections including 5 with sternal wound infections (three bacteremic), 6 with bacteremia, 1 with prosthetic valve endocarditis, and 3 with severe venous donor graft site infections. Eight major infections occurred in patients receiving cephalothin prophylaxis and three in patients receiving cefamandole, with all five sternal wound infections occurring in the cephalothin group. Postoperative pathogens responsible for the major infections included gram-negative aerobes in 5 patients, Staphylococcus aureus in 4, and Staphylococcus epidermidis in 2. Preoperative colonizing staphylococcal isolates were not predictive of postoperative staphylococcal pathogens. Although there was no statistically significant difference in rate of major postoperative infectious complications using either cephalothin or cefamandole prophylaxis, there was a trend in favor of cefamandole. Gram-negative aerobes are becoming increasingly important pathogens in this setting.

The changing clinical profile of coronary artery bypass graft patients, 1970-89.

OBJECTIVE: To review the changing clinical profile of isolated coronary artery bypass graft (CABG) surgery patients at the University of Alberta Hospitals during the past two decades. DESIGN: Data were obtained retrospectively by review of patients' hospital charts and cardiologists' charts. The three patient cohorts consisted of the first 411 consecutive patients who underwent isolated CABG surgery between 1970 and 1974, 302 consecutive patients who had CABG surgery in 1984 and 346 consecutive patients who had the operation in 1989. RESULTS: Patients who underwent CABG surgery in 1984 and 1989 were older than patients undergoing the same operation in the 1970s. Emergency and/or urgent operations and the number of patients with prior myocardial infarct were increased significantly in 1984 and 1989. The incidence of patients with multiple vessel disease and left main stem stenosis increased significantly over the two decades. The number of bypass grafts per patient and the use of internal mammary grafts have increased since 1970. The endarterectomy procedure was performed less frequently in 1984 and 1989. The use of radial artery grafts has been discontinued. Perioperative mortality remained stable throughout the study period despite an increasing incidence of high risk patients. The major cause of death was pump failure. The incidence of peripostoperative myocardial infarct was higher in the 1970s. A multivariate analysis of the 1984 and 1989 cohorts was performed to identify temporal trends in risk factors. Emergency surgery, preoperative heart failure, age (older than 65 years), prior CABG surgery and preoperative renal failure are significant predictors of operative motility. CONCLUSIONS: The clinical profile of patients for isolated CABG surgery has changed over the years. The mortality rate has been stable over two decades despite the advancement of medical and surgical practices, representing a balance of increasingly high risk patients presenting for CABG surgery.

Long term clinical outcomes following isolated mitral valve replacement.

OBJECTIVE: This study reviews the short and long term outcomes of patients who underwent isolated mitral valve replacement at the University of Alberta Hospitals during the past decade. DESIGN: Data were obtained retrospectively by review of patients' hospital charts, cardiologists' follow-up charts, contact with patients' physicians, and direct telephone or mail contact with patients and/or their surviving relatives. RESULTS: The clinical outcomes of 198 consecutive patients (124 women and 74 men) who underwent isolated mitral valve replacement from January 1981 to December 1990 at the University of Alberta Hospital were reviewed. Overall early operative mortality was 11%. Deaths were mainly related to pump failure and previous mitral valve replacement. Late mortality was 17%. Follow-up data were available except in five patients. Average follow-up was 6.3 years. Overall cumulative survival was 72.9 +/- 3.4% at five years and 63.1 +/- 4.8% at 10 years. The cumulative freedom from complications was 64.3 +/- 3.9% and 36.4 +/- 4.9% at five and 10 years, respectively. Long term survival rates obtained after isolated mitral valve replacement are higher than those reported in series of medically treated patients with mitral valve disease. CONCLUSIONS: Mitral valve replacement can prolong survival as well as improve symptoms in patients with symptomatic mitral valve disease.

Experimental study of selected small caibre arterial grafts.

1. The most ideal replacement for a small calibre artery segment is a similar sized autogenous arterial conduit. 2. Autogenous venous segments, although functional replacements for small calibre arteries, undergo structural changes which may prove detrimental to function. 3. At this stage of their development, fabric grafts cannot be considered as adequate replacements for small calibre arteries.

Computerized database for coronary bypass surgery.

A computer-assisted system has been developed to store, retrieve and analyze medical and surgical data on patients undergoing coronary bypass surgery. The analysis ranges from a simple summary tabulation to a more advanced prognostic evaluation of the risk of coronary bypass in an individual candidate for the operation. Data can be displayed on the terminal's screen or printed in a hard copy and used for clinical or administrative purposes. The system can be operated with no knowledge of computers or programming and requires only minimal typing skills.

A five year study of the incidence of valve-related complications with the Omniscience cardiac prosthesis.

A total of 228 Omniscience cardiac valve prostheses were implanted in 210 patients at two hospitals in Canada from November, 1979 to August, 1984. The 184 operative survivors were followed for a mean duration of 28.5 months (maximum 62.7 months) and for a total of 438 patient-years. Actuarial analysis for AVR, MVR, and all patients showed survival probabilities at five years of 97.2%, 98.9%, and 97.0% respectively. The five-year actuarial probabilities of remaining free of any thrombotic complications were 96.9% for AVR, 96.4% for MVR, and 95.7% overall. When considering only serious thrombotic complications (thromboembolism with deficit or valve thrombosis), the event-free rates are 100% for AVR, 98.9% for MVR, and 98.6% for the overall patient group at five years. These rates for survival and freedom from thrombotic complication demonstrate the clinical safety and effectiveness of the Omniscience prosthesis. In addition, there were no cases of structural failure or intrinsic mechanical malfunction of the prosthesis.