Albert Starr

Continuous intravenous insulin infusion reduces the incidence of deep sternal wound infection in diabetic patients after cardiac surgical procedures

BACKGROUND Diabetes mellitus is a risk factor for deep sternal wound infection after open heart surgical procedures. We previously showed that elevated postoperative blood glucose levels are a predictor of deep sternal wound infection in diabetic patients. Therefore, we hypothesized that aggressive intravenous pharmacologic control of postoperative blood glucose levels would reduce the incidence of deep sternal wound infection. METHODS In a prospective study of 2,467 consecutive diabetic patients who underwent open heart surgical procedures between 1987 and 1997, perioperative blood glucose levels were recorded every 1 to 2 hours. Patients were classified into two sequential groups: the control group included 968 patients treated with sliding-scale-guided intermittent subcutaneous insulin injections (SQI); the study group included 1,499 patients treated with a continuous intravenous insulin infusion in an attempt to maintain a blood glucose level of less than 200 mg/dL. There were no differences between these groups with respect to age, sex, procedure, bypass time, antibiotic prophylaxis, or skin preparation methods. RESULTS Compared with subcutaneous insulin injections, continuous intravenous insulin infusion induced a significant reduction in perioperative blood glucose levels, which led to a significant reduction in the incidence of deep sternal wound infection in the continuous intravenous insulin infusion group (0.8% [12 of 1,499]) versus the intermittent subcutaneous insulin injection group (2.0% [19 of 968], p = 0.01 by the chi2 test). Multivariate logistic regression revealed that continuous intravenous insulin infusion induced a significant decrease in the risk of deep sternal wound infection (p = 0.005; relative risk, 0.34), whereas obesity (p < 0.03; relative risk, 1.06) and use of an internal thoracic artery pedicle (p = 0.1; relative risk, 2.0) increased the risk of deep sternal wound infection. CONCLUSIONS Use of perioperative continuous intravenous insulin infusion in diabetic patients undergoing open heart surgical procedures significantly reduces major infectious morbidity and its associated socioeconomic costs.

Glucose Control Lowers the Risk of Wound Infection in Diabetics After Open Heart Operations

BACKGROUND Elevated blood glucose levels in the postoperative period are associated with an increased risk of deep wound infection in diabetic individuals undergoing open heart operations at Providence St. Vincent Hospital. METHODS Of 8,910 patients who underwent cardiac operations between 1987 and 1993, 1,585 (18%) were diabetic. The rate of deep sternal wound infections in diabetic patients was 1.7%, versus 0.4% for nondiabetics. Nine hundred ninety patients had their operation before implementation of the protocol and 595 after implementation. Charts of all diabetic patients were reviewed. Mean blood glucose levels were calculated from documented results of finger-stick glucometer testing. RESULTS Thirty-three diabetic patients suffered 35 deep wound infections: 27 sternal (1.7%) and eight at the donor site (0.5%). Infected diabetic patients had a higher mean blood glucose level through the first 2 postoperative days than noninfected patients (208 +/- 7.1 versus 190 +/- 0.8 mg/dL; p < 0.003) and had a greater body mass index (31.5 +/- 1.4 versus 28.6 +/- 0.1 kg/m2; p < 0.05). Multivariable logistic regression showed that mean blood glucose level for the first 2 days (p = 0.002), obesity (p < 0.002), and use of the internal mammary artery (p < 0.02) were all independent predictors of deep wound infection. Institution of a protocol of postoperative continuous intravenous insulin to maintain blood glucose level less than 200 mg/dL was begun in September 1991. This protocol resulted in a decrease in blood glucose levels for the first 2 postoperative days and a concomitant decrease in the proportion of patients with deep wound infections, from 2.4% (24/990) to 1.5% (9/595) (p < 0.02). CONCLUSIONS The incidence of deep wound infection in diabetic patients was reduced after implementation of a protocol to maintain mean blood glucose level less than 200 mg/dL in the immediate postoperative period.

Prosthetic Valvular Endocarditis A 12-Year Review

A retrospective examination was made of a total of 48 patients with infected prosthetic cardiac valves implanted in 1,236 patients during 1960-1972. Survival rate of the valvular infections was 40%. The purpose of the study was to determine the factors which aided or decreased patient survival and to develop a program of treatment with antimicrobial agents. Numerous antimicrobics and a variety of dosage schedules were used. Of 19 surviving patients, medical treatment alone was effective in 14, despite the continued presence of a valvular prosthesis. Reoperation was successful in five of nine patients. Lifelong chemoprophylactic or suppressive therapy was shown to be unnecessary to prevent relapse in 12 survivors. Prompt surgical replacement is indicated if antimicrobial therapy fails to eradicate infection of a prosthetic valve. A more systematic approach to antimicrobial therapy should improve survival of medically treated infections. Recommendations are made for prevention and treatment of prosthetic valvular endocarditis.

Influence of Aortocoronary Bypass Surgery on Left Ventricular Performance

Abstract Quantitative analysis of left ventricular cineangiocardiograms was performed before and after aortocoronary-vein-bypass operations for angina pectoris in 14 selected patients. Eight patients with anatomically successful results had a decrease in left ventricular end-systolic volume, and an increase in ejection fraction and the rate of circumferential fiber shortening at the ventricular equator. In two, improvement in the motion of akinetic regions of the ventricular wall was found. Six other patients had anatomically unsatisfactory results, usually because of occlusion of the graft. Ejection fraction and fiber-shortening rate fell in these, and the end-systolic volume was higher after operation. End-diastolic volume was similar in both groups and was not consistently altered by operation. In patients without severe depression of ventricular performance, ventricular function improved when the operation was technically successful. Deterioration of function accompanied graft occlusion.

Actuarial Analysis of Surgical Results: Rationale and Method

The use of time-related methods of statistical analysis is essential for valid evaluation of the long-term results of a surgical procedure. Accurate comparison of two procedures or two prosthetic devices is possible only when the length of follow-up is properly accounted for. The purpose of this report is to make the technical aspects of the acturial, or life table, method easily accessible to the surgeon, with emphasis on the motivation for and the rationale behind it. This topic is illustrated in terms of heart valve prostheses, a field that is rapidly developing. Both the authors and readers of articles must be aware that controversies surrounding the relative merits of various prosthetic designs or operative procedures can be settled only if proper time-related methods of analysis are utilized.

Aortic Replacement Clinical Experience with a Semirigid Ball-Valve Prosthesis

A ball-valve prosthesis for aortic replacement has been described which, while it is similar to the mitral ball valve in terms of materials and construction, is quite different in sewing margin and internal geometry. Implantation is greatly facilitated by the flexibility of the prosthesis in terms of external diameter, and by the availability of a full set of varying sizes for obtaining a proper fit. Widening of the aortic root by patch grafting has not been necessary. Long-term survival has been achieved in the dog, and early clinical results are most promising.While the selection of the ideal aortic valvular replacement must await further experience with all types of prostheses, continued evaluation of the ball valve in the aortic position, in carefully chosen patients, is indicated.

Preoperative criteria predictive of late survival following valve replacement for severe aortic regurgitation

Forty-five patients underwent aortic valve replacement (AVR) for severe isolated aortic regurgitation from 1973 to 1979. There were two (4.4%) hospital deaths, both functional class IV. Six patients with mechanical prosthesis not receiving anticoagulants were excluded from further analysis. These data relate to 39 patients; the two operative deaths, 35 patients with mechanical prosthesis receiving anticoagulants, and two with bioprosthesis. There were three late cardiac deaths with 5-year survival 85%; average annual mortality rate of 3%. The 5-year survival with pre-AVR left ventricular (LV) ejection fraction greater than or equal to 0.45 was 87% vs 54% less than 0.45, (p less than 0.04); cardiac index greater than or equal to 2.5 L/min/m2 92% vs 66% less than 2.5 (p less than 0.04); mean VCF greater than or equal to 0.75 vs less than 0.75 circ/sec (p less than 0.09); end-diastolic pressure less than or equal to 20 vs greater than 20 mm Hg (p less than 0.08). Late survival was not significantly different between pre-AVR functional class I and II vs class III and IV; LV end-diastolic volume index greater than or equal to 210 vs less than 210 ml/m2; LV end-systolic volume index greater than or equal to 110 vs less than 110 ml/m2; and LV mass greater than or equal to 240 vs less than 240 gm/m2. With ejection fraction greater than or equal to 0.50 there was only one operative death (functional class IV) and no late cardiac deaths. Thus late survival following aortic valve replacement for severe isolated aortic regurgitation is better predicted preoperatively by the LV systolic pump function variables of ejection fraction and cardiac index than by LV diastolic parameters and clinical status.

Overview of the nature of vasoconstriction in arterial grafts for coronary operations

Many vasoconstrictors (spasmogens) may cause arterial graft spasm; however, there is lack of an overview of the nature of vasoconstriction in grafts. This study was designed to investigate the response of three major arterial grafts currently used for coronary artery bypass grafting to various vasoconstrictor substances. Segments of three arterial grafts (gastroepiploic [GEA], n = 28; internal mammary [IMA], n = 213; inferior epigastric [IEA], n = 24) taken from patients undergoing coronary artery bypass grafting were studied in organ baths under a physiologic pressure. Cumulative concentration-contraction curves were established for the following vasoconstrictor substances: endothelin-1, U46619, prostaglandin F2 alpha, norepinephrine, methoxamine, phenylephrine, 5-hydroxytryptamine, and potassium chloride (K+). In IMA, the highest contraction force was induced by U46619 (5.69 +/- 0.48 g), endothelin-1 (4.43 +/- 0.4 g), PGF2 alpha (6.29 +/- 1.42 g), and K+ (4.58 +/- 0.5 g). Internal mammary artery is highly sensitive to endothelin-1 (EC50, -8.13 +/- 0.08 log M) and U46619 (EC50, -8.21 +/- 0.21 log M) (lower than any other vasoconstrictors, p < 0.001). Next sensitive vasoconstrictors were PGF2 alpha and norepinephrine. 5-Hydroxytryptamine induced significantly higher contraction force in the IMA without endothelium (2.8 +/- 0.64 g versus 1.4 +/- 0.23 g, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Up to thirty-year survival after aortic valve replacement in the small aortic root

Aortic valve replacement (AVR) in the small aortic root has been reported to be associated with obstruction of left ventricular output. This study was designed to investigate the determinants of long-term survival after the implantation of small size prostheses. From September 1961 to December 1993, 2,977 patients underwent isolated aortic valve replacement at our institution. Of these patients, 447 who were older than 18 years received small size (21 mm or less) prostheses. Long-term survival was investigated in the 404 patients who survived operation (more than 30 days) with 92% follow-up completeness (mean +/- deviation 7.1 +/- 6.4; maximum, 31 years). The age was younger than 50 years in 62 patients, 50 to 59 years in 60, 60 to 69 years in 99, 70 to 79 years in 138, and 80 to 94 years in 45; 67% were men. Thirty patients (7%) had previous AVR. Prosthesis usage included early Starr-Edwards models in 130 (32%), current Starr-Edwards (model 1260 since 1969) in 50 (12%), Carpentier-Edwards (porcine) in 113 (28%), and other prostheses in 111 patients (27%). One hundred sixteen patients (26%) had concomitant coronary artery bypass grafting (CABG). Eleven variables (age divided as above, sex, preoperative functional class, body surface area [BSA], small BSA [less than 1.6, 1.7, 1.8, or 1.9 m2], period of operation, previous AVR, type of prosthesis, size of prosthesis, concomitant CABG, and re-replacement) were investigated with regard to the long-term survival by the Kaplan-Meier method, and age, concomitant CABG, and type of prosthesis were significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Infective Endocarditis: Ten-Year Review of Medical and Surgical Therapy

BACKGROUND Infective endocarditis is a complex disease process. Optimal outcome often requires both medical and surgical expertise. The need for and timing of surgical intervention is controversial and continues to evolve in parallel to advancements in diagnosis and treatment. Our experience with the treatment of infective endocarditis is reviewed herein. METHODS A retrospective review was compiled of 140 consecutive patients who fulfilled the modified von Reyn criteria for the diagnosis of endocarditis between January 1982 and April 1992. RESULTS Patient characteristics, symptoms, and risk factors are described. Follow-up averaged 3.5 +/- 0.8 years and totaled 491 patient-years. New York Heart Association functional class at presentation had a significant influence on survival (p < 0.0001). Long-term survival was significantly greater (p = 0.036) in patients treated medically/surgically than those treated with medical therapy alone (75% versus 54% at 5 years). Medical treatment of aortic and prosthetic endocarditis was associated with higher mortality (58% and 67%, respectively) when compared with combined medical/surgical treatment (28% and 38%, respectively). Among the survivors, New York Heart Association class at follow-up was better (p < 0.0001) in the medical/surgical group (1.05 +/- 0.04) versus the medical treatment group (1.70 +/- 0.14). CONCLUSIONS Combined medical/surgical treatment for infective endocarditis is associated with improved survival. Patients with aortic or prosthetic endocarditis are identified as subgroups that benefit most from surgical intervention. Valvular dysfunction incited by the infective process is an important factor that should be weighed carefully in the therapeutic decision.