Hugh E. Scully

Deep Sternal Wound Infection: Risk Factors and Outcomes

BACKGROUND Deep sternal wound infection (DSWI) is a serious complication of cardiac operations performed by median sternotomy. We attempted to define the predictors of DSWI and to describe the outcomes of two treatment strategies used at our institution. METHODS Retrospective review was performed using prospectively gathered data on 12,267 consecutive cardiac surgical patients from 1990 to 1995. Chart review was performed on all patients in whom DSWI developed, and follow-up was obtained on 100% of these patients. RESULTS Deep sternal wound infections developed in 92 patients (incidence 0.75%). Multivariable predictors for development of DSWI in all patients were (odds ratios and 95% confidence intervals in parentheses) (1) diabetes mellitus (2.6; 1.7 to 4.0) and (2) male sex (2.2; 1.3 to 3.9). In patients receiving coronary artery bypass grafting alone, independent predictors were (1) bilateral internal thoracic artery grafts (3.2; 1.1 to 8.9), (2) diabetes (2.7; 1.6 to 4.3), and (3) male sex (1.8; 0.9 to 3.7). For all other patients, predictors were (1) age more than 74 years (3.3; 1.1 to 10.1), (2) male sex (3.0; 1.1 to 8.1), and (3) diabetes (2.3; 0.9 to 5.8). Bilateral internal thoracic artery grafts increased the risk of DSWI in all subgroups of coronary artery bypass graft patients, particularly in diabetics who had a 14.3% incidence of DSWI after bilateral internal thoracic artery grafting. Patients with DSWIs received either sternal debridement with primary closure (n=45) or sternectomy with flap reconstruction (n=46). The 6-month freedom from adverse event rate (ie, readmission, reoperation, or death) was 76% for both groups of patients. CONCLUSIONS Male sex and diabetes are predictors of DSWI in all cardiac surgical patients. Bilateral internal thoracic artery grafting may be contraindicated in diabetic patients.

Technique of successful clinical double-lung transplantation.

Lung transplantation has become a successful method in the therapy for end-stage pulmonary disease. While single-lung transplantation provides benefit to patients with pulmonary fibrosis, bilateral lung transplants are required for septic or emphysematous lung disease. We describe the technique employed in 6 patients to transplant en bloc both lungs with the recipient heart left in place. The lungs are connected by a left atrial cuff, main pulmonary artery, and trachea. The completed implantation has a tracheal anastomosis securely wrapped in omentum, a left atrial anastomosis posterior to the heart, and a pulmonary artery anastomosis anteriorly. Airway ischemia resulted in the death of 1 patient. This procedure allows complete excision of all diseased pulmonary tissue, retention of the recipients own heart, and separate excision of the donor heart for use in another recipient, thereby markedly increasing the supply of donor lungs for transplantation.

Permanent Cardiac Pacing After Open-heart Surgery: Acquired Heart Disease

Retrospective review of 5,942 patients who underwent open‐heart surgery for acquired heart disease revealed that 123 patients (2.1%) required permanent cardiac pacing postoperatively; 4.6% of these underwent predominantly valvular surgery and 0.6% had coronary bypass. The most important factors appeared to be: 1) preoperative evidence of a conduction disorder; 2) advanced patient age; 3) dense calcium in the aortic annulus; 4) valvular surgery and, especially, tricuspid valve surgery; and 5) poor myocardial protection. Postoperative permanent pacing had a considerable impact on patient morbidity from maintenance operations; most complications were lead‐related problems.

Evolving Indications for Preoperative Intraaortic Balloon Pump Assistance

Over a two-year period about 1,000 operations were performed with cardiopulmonary bypass. Intraaortic balloon pump assistance (IABP) was employed on 150 occasions, and a review of these has permitted clarification of the indications for its use. Sixty patients had IABP for carcinogenic shock either after infarction or cardiotomy, and 37 (62%) survived. Preoperative IABP in 90 high-risk patients resulted in survival for 79 (88%). The indications for prophylactic IABP included: (1) relief of severe pain, which occurred in 42 patients with acute coronary insufficiency, (2) improvement in the coronary perfusion pressure, which was accomplished in 20 patients with significant left main coronary artery occlusion or its equivalent, and (3) protection of left ventricular function, which war carried out in 28 patients with an LV ejection fraction of less than 0.40. The significance of the preoperative endocardial viability ratio (EVR) in relation to prophylactic IABP was also assessed: an EVR below 0.70 appears to be an indication for preoperative IABP.

Reoperative mitral valve replacement: importance of preservation of the subvalvular apparatus.

BACKGROUND Preservation of the subvalvular apparatus has been demonstrated to be beneficial during first-time mitral valve replacement (MVR), but has not been fully examined in reoperative (redo) MVR. The purpose of this study was to analyze outcomes in a large cohort of redo MVR patients, focusing on the effect of subvalvular preservation on mortality. METHODS We undertook a review of prospectively gathered data on patients undergoing MVR, with or without concomitant cardiac procedures, at our institution from 1990 to 1999. Predictors of mortality were determined by stepwise logistic regression. RESULTS A total of 1,521 consecutive MVR patients were analyzed, of which, 513 (34%) had undergone one or more previous MV procedures. In-hospital mortality occurred in 6.9% of first-time MVR patients versus 9.0% in redo patients (p = 0.13). The number of prior MV operations ranged from one to five in redo MVR patients, with 115 patients (22% of redos) having two or more. In redo MVR patients, preservation of the native posterior subvalvular apparatus was performed in 103 patients (21%), whereas native anterior and posterior preservation was performed in 31 patients (6%). Gore-Tex neochordal construction was performed in 135 redo MVR patients (26%). Perioperative mortality occurred in 3.6% of redo MVR patients with a preserved subvalvular apparatus (native tissue and/or Gore-Tex reconstruction) versus 13.3% of redo patients without preservation (p < 0.001). Independent predictors of mortality in redo MVR patients were (in decreasing order of magnitude) failure to preserve the subvalvular apparatus, preoperative renal failure, previous stroke/transient ischemic attack, left ventricular dysfunction (left ventricular ejection fraction <40%), and urgent timing. CONCLUSIONS Redo MVR can be performed with an acceptable risk of mortality. Although preservation of the subvalvular apparatus may increase operative complexity, we recommend subvalvular preservation in order to decrease the risk of early mortality.

The Determinants of Mortality and Morbidity after Multiple-Valve Operations

The factors predictive of hospital mortality and morbidity after contemporary multiple-valve surgical procedures were identified to develop strategies to improve the results of such procedures. Preoperative, intraoperative, and postoperative information was collected prospectively on 90 consecutive patients undergoing surgical procedures between 1982 and 1984. The operative mortality was 5.6%, and the incidence of postoperative low-output syndrome was 16.7%. Multivariate logistic regression analysis identified tricuspid regurgitation (p less than .03, improvement-of-fit chi square) and the aortic valve lesion (p less than .03) as the independent predictors of postoperative complications (mortality or low-output syndrome). Patients with tricuspid regurgitation and right ventricular decompensation and those with aortic stenosis and left ventricular hypertrophy had limited ventricular functional reserve and faced an increased risk. Improved methods of myocardial protection may reduce the risk in these patients.

Pathologic analysis of 19 heart valves with silver-coated sewing rings.

Abstract  Objective: The St. Jude Medical Silzone® (Silzone®) mechanical heart valve was voluntarily recalled (January 2000) due to an unusually high incidence of paravalvular leaks. We present the first series of human morphological data on the failure of these valves.

A Comparison of Volume Loading and Atrial Pacing Following Aortocoronary Bypass

Although cold potassium cardioplegia provides adequate myocardial protection, transient hemodynamic and metabolic instability occasionally occurs after uncomplicated coronary bypass surgery. Two methods to increase cardiac output were compared 2 to 6 hours postoperatively in 24 patients recovering from elective coronary bypass operation. Volume loading increased cardiac index (CI) from 2.1 +/- 0.5 to 2.7 +/- 0.6 L/min/m2 by increasing left atrial pressure (LAP) from 8.6 +/- 3.6 to 13.0 +/- 4.1 mm Hg. Atrial pacing at a rate of 112 +/- 8 beats per minute increased CI from 2.4 +/- 0.5 to 2.7 +/- 0.8 L/min/m2 without a change in LAP. Ejection fraction by nuclear angiography did not change, but the calculated left ventricular end-diastolic volume index (stroke index/ejection fraction) increased with volume loading and decreased with atrial pacing--a decrease in diastolic compliance. Myocardial oxygen extraction did not change, but myocardial lactate extraction increased with volume loading and decreased with atrial pacing. Coronary sinus blood flow was measured in 5 patients and increased with both methods studied. Volume loading demonstrated that myocardial performance was normal and myocardial metabolism increased commensurate with the increase in work. Atrial pacing increased CI but resulted in anaerobic metabolism and a decrease in diastolic compliance. Volume loading rather than atrial pacing will improve CI without producing ischemia in the early postoperative period.

Five-Year Follow-up of Hancock Pericardial Valves: Management of Premature Failure

The durability and function of bovine pericardial valves are dependent upon design, preservation, patient factors (age, sex), and site of valve implantation. In 1983, a shelf recall of all Hancock bovine pericardial valves (HPV) was instituted by the manufacturer. This report represents the results of an organized 5‐year follow‐up in a hospital Prosthetic Valve Registry of 129 HPV implanted in 122 patients (79 males, 43 females) between May 1982 and April 1985 using echo Doppler and careful clinical evaluation. Mean age was 56 ± 15 years. There were 81 AVR, 33 MVR, 7 DVR, and 1 TVR. Concomitant coronary bypass was performed in 38 patients (31%). Surgery was on a redo basis in 25 patients (20%), urgent in 14 (11%), and for SBE in 8 patients (7%). There were seven hospital deaths (5.7%). Mean follow‐up was 44 months (maximum 66 months) for 114 patients (99% complete), representing 417 patient years. There have been 20 late deaths (18%), of which 7 were directly valve related. Linearized frequency of major events (per pt‐yr) was: thromboembolism, 1.6%; anticoagulant related hemorrhage, 0.8% (1 late death); prosthetic valve endocarditis 1.3%; primary tissue failure, 5.8%. Patient symptomatology was a more accurate predictor of bioprosthetic failure requiring reoperation than echo Doppler studies, which were completed in 74 of 97 patients examined during scheduled follow‐up visits. Twenty‐four of the 96 patients (25%) have required re‐replacement at a mean interval of 44 months (27–59 months) from initial implantation. This was due to vertical shear starting at the top of the strut anchoring commissural attachments in every case. There have been two redo operative deaths (8%), one in a patient with severe prosthetic endocarditis and one in a patient requiring double valve rereplacement with extensive coronary artery disease and biventricular failure. At 60 months, actuarial patient survival was 65% ± 14% and freedom from valve‐related complications was 54% ± 13%. There was no difference in rate of failure in relation to valve site or patient sex or age. We conclude that structural design has led to premature failure of Hancock bovine pericardial valves and predict that an increasing number will fail and should require interval re‐replacement.

Cardiac surgery in a fixed-reimbursement environment

Hospital and physician services in Canada are funded by public (government) sources. This article will describe the practice of cardiac surgery in this setting. Federal legislation has prescribed the principles of accessibility, universality, comprehensiveness, portability, and public administration for essential healthcare services in Canada. Provincial and territorial governments are responsible for the provision of services, receiving federal tax and cash transfers that supplement provincial/territorial funds for hospital, physician, and community health services. Hospitals negotiate annually for global budgets. Physicians work as independent contractors in hospitals (and communities) and are usually paid as specified by fee-for-service contracts negotiated at intervals with governments. Cardiac surgical services have been planned conjointly with government. Forty-two centers in Canada serve a population of 28 million. All but three of these centers are located in tertiary teaching hospitals; all but one do more than 200 pumps annually. The rate of cardiac operations is 80 per 100,000 population. In Ontario, the Provincial Adult Cardiac Care Network makes recommendations to governments about the distribution of the 7,600 pumps annually (population, 11 million), rationalizing waiting lists based on an urgency rating scale. Patients requiring emergent/urgent operations are well served. The average waiting time for an elective cardiac operation is 10.5 weeks. The waiting list mortality is less than 0.5%. The Provincial Adult Cardiac Care Network also determines the placement of new programs and participates in creating hospital funding formulas developed from a combination of resource and acuity intensity weighting. Most surgeons hold full-time academic appointments but are funded largely by practice income. Surgical fees average