Aurelio Chaux

Increased Mortality of Women in Coronary Artery Bypass Surgery: Evidence for Referral Bias

STUDY OBJECTIVE To determine whether differences in referral reasons explain the higher operative mortality of women in coronary artery bypass surgery. DESIGN Case series. SETTING A tertiary care, private teaching hospital. PATIENTS Consecutive patients who had isolated coronary artery bypass surgery between 1982 and 1987 (total, 2297; 79% male and 21% female). MEASUREMENTS AND MAIN RESULTS The inhospital mortality rate was significantly higher for women than for men (4.6% compared with 2.6%; P = 0.036; 95% CI for difference in mortality, 0% to 4.0%). Women were older than men (mean, 68.2 and 64.0 years, respectively; P less than 0.001), and a higher percentage of women were referred with unstable angina (P = 0.007), postmyocardial infarction angina (P = 0.029), congestive heart failure (P less than 0.001), and New York Heart Association class IV symptoms (66% compared with 45%, P less than 0.001). More men were referred with a history of an abnormal exercise test (P less than 0.001), and patients referred because of a positive exercise test had a lower mortality (P less than 0.001). Using multivariate analysis, adjustment for the higher preoperative functional class of women and for age accounted for all of the difference in mortality between men and women (odds ratio, 1.04; CI, 0.60 to 1.79; P = 0.89). After correction for functional class alone, there continued to be no significant difference in mortality between men and women (P = 0.40). CONCLUSIONS Differences in functional class and age account for the higher operative mortality of women in coronary bypass surgery. Women are referred for coronary bypass surgery later in the course of their disease than men, and later referral may increase their changes of operative death.

The St. Jude valve. Thrombolysis as the first line of therapy for cardiac valve thrombosis.

BackgroundThrombolytic therapy is a promising alternative to valve replacement in the management of prosthetic valve thrombosis. We sought to determine the short- and long-term results of treating thrombosed St. Jude heart valves with thrombolytic therapy as the primary treatment modality. Methods and ResultsBetween March 1978 and December 1991, 988 patients underwent implantation of St. Jude prosthetic valves at our medical center, and all patients with thrombosed valves were identified prospectively. During this period, 17 patients (13 women; mean age, 66.8±19.0 years) developed prosthetic valve thrombosis (11 aortic, six mitral). In six patients, Coumadin was stopped in preparation for elective surgery. The clinical presentation was congestive heart failure in 13, syncope and fatigue in two, and a cerebrovascular accident in one; one patient was asymptomatic. The average duration of symptoms was 11.7±12.0 days (range, 1–45 days). Anticoagulation was subtherapeutic in all but one patient at the time of presentation. Cinefluoroscopy was the primary method used for diagnosis and was also used to follow the response to therapy. Twelve patients were treated medically (10 with thrombolytic therapy and two with heparin), three were treated surgically, and two were diagnosed at autopsy. Of the 12 medically treated patients, 10 had marked improvement in leaflet movement and symptoms within 12 hours. Thus, 10 of 12 patients (83%) had a satisfactory response to medical therapy alone. No medically treated patient died or had a major complication resulting in permanent damage. However, four of the 12 medically treated patients had minor complications, including a transient episode of facial weakness in one patient, hematomas in two, and epistaxis in one. Late rethrombosis recurred in two patients in the medically treated group and was successfuly retreated with thrombolytic therapy. At 3 months, all patients were alive and well. ConclusionsThrombolytic therapy can be used as the first line of therapy for thrombosed St. Jude valves with a low risk of permanent side effects and excellent chances of success. In most cases, surgery can be reserved for patients who do not respond to thrombolytic therapy.

Ten-year experience of cardiac surgery in patients aged 80 years and over.

Five hundred twenty-eight consecutive patients aged 80 years and over (mean age, 83.1 +/- 2.7 years) underwent cardiac operations with hypothermia (mean, 21.9 degrees +/- 2.2 degrees C), hyperkalemic cardioplegia, and cardiopulmonary bypass in a 10-year period. Fifty-six percent of the patients were male. Preoperatively, 68% of the patients were in New York Heart Association functional class IV, and 31% were in class III. Among them, 303 patients had isolated coronary artery bypass grafting (CABG) (group I), 132 had aortic valve replacement only or combined with CABG (group II), 42 had mitral valve replacement only or combined with CABG (group III), 31 had mitral valve repair and CABG (group IV), and 20 had double-valve procedure only or combined with CABG (group V). The 30-day or in-hospital mortality was 8.3% in group I, 4.5% in group II, 29% in group III, 23% in group IV, and 30% in group V. Total 30-day or in-hospital mortality was 10.6%. One-year and 5-year actuarial survival rates were as follows: group I, 82% and 62%; group II, 85% and 58%; group III, 61% and 37%; group IV, 56% and 19%; and group V, 63% and 15%. Total 1-year and 5-year actuarial survival were 79% and 54%. At follow-up (mean, 2 years), 70% of overall survivors reported that their general health had improved. Our experience demonstrates that for select patients aged 80 years and over with unmanageable cardiac symptoms, CABG and aortic valve replacement groups had better results in improving quality of life as compared with patients having mitral or combined procedures.

Treatment of severe platelet dysfunction and hemorrhage after cardiopulmonary bypass: reduction in blood product usage with desmopressin.

Impairment of platelet function commonly occurs after cardiopulmonary bypass, and may result in substantial bleeding. Because desmopressin acetate (a synthetic analogue of vasopressin) shortens bleeding time in a variety of platelet disorders, a controlled clinical trial of intravenous desmopressin was performed in 39 patients with excessive mediastinal bleeding (greater than 100 ml/h) and a prolonged template bleeding time (greater than 10 minutes) more than 2 hours after termination of cardiopulmonary bypass. Twenty-three desmopressin recipients and 16 control patients (no desmopressin) were similar in surgical procedure, pump time, platelet count, template bleeding time and amount of bleeding before therapy (p = NS). Compared with the control group, the patients receiving desmopressin (20 micrograms; mean 0.3 micrograms/kg) utilized fewer blood products (29 +/- 19 versus 15 +/- 13 units/patient; p less than 0.05), especially platelets (12 +/- 9 versus 4 +/- 7 units/patient; p = 0.004), while achieving a similarly effective reduction in mediastinal bleeding (4.8- and 4.3-fold, p = 0.001 for both). Severe platelet dysfunction was partially corrected within 1 hour after desmopressin infusion, during which interval no blood products were administered: the template bleeding time shortened (from 17 to 12.5 minutes, p less than 0.05), whereas the platelet count remained unchanged (at 96 +/- 35 and 105 +/- 31 X 10(3)/mm3, p = NS). The plasma levels of two factor VIII components increased: procoagulant activity (VIII:C) from 0.97 +/- 0.43 to 1.52 +/- 0.74 units/ml (p less than 0.05) and von Willebrand factor (VIII:vWF) from 1.28 to 1.78 units/ml (p less than 0.05); these increases correlated with the shortening of the bleeding time (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Bileaflet, tilting disc and porcine aortic valve substitutes: In vitro hydrodynamic characteristics

The desire for a low profile mechanical valve with better fluid dynamic performance led to the design and development of the St. Jude Medical bileaflet prosthesis. Comparative in vitro flow studies indicate that it has better pressure drop characteristics than the Björk-Shiley (convexo-concave) and Carpentier-Edwards porcine valves in current clinical use, especially in the small sizes. In the 21 to 27 mm aortic valve size range the St. Jude valve has an average performance index of 0.66, compared with 0.46 and 0.32 for the Björk-Shiley and Carpentier-Edwards valves, respectively. In contrast, the St. Jude valve has larger regurgitant volumes than both the Björk-Shiley and Carpentier-Edwards valves. Velocity measurements with a laser-Doppler anemometer indicate relatively centralized flow with small amounts of turbulence downstream of the St. Jude valve. The flow is unevenly distributed between the central and side orifices. The turbulent shear stresses are, however, large enough to cause sublethal or lethal damage to blood elements. Wall shear stresses are smaller than those measured downstream of the Björk-Shiley valve. Regions of flow separation were observed just downstream from the sewing ring, which could lead to excess tissue growth along the sewing ring. The results of this study indicate that overall in vitro fluid dynamic performance of the St. Jude valve is superior to that of the two other commonly used prostheses.

Intraoperative Doppler color flow mapping for assessment of valve repair for mitral regurgitation

The ability of color Doppler flow mapping to provide intraoperative information about mitral regurgitation (MR) severity and to evaluate adequacy of mitral valve repair was assessed by performing color Doppler echocardiography immediately before and after cardiopulmonary bypass, with the transducer placed directly on the epicardium. In 56 patients, the degree of MR by intraoperative color Doppler correlated well with left ventricular angiography (kappa = 0.80) and with closed-chest preoperative color Doppler (kappa = 0.84) and had good interobserver reproducibility (kappa = 0.88). Good correlation was also seen between closed-chest color Doppler and angiography (kappa = 0.75). After mitral valve repair in 18 patients (15 ischemic MR, 3 cleft valves), color Doppler was used to assess severity of residual MR intraoperatively and postoperatively. Intraoperative color Doppler identified satisfactory repair (MR less than or equal to 2+) in 15 patients and failure (MR greater than or equal to 3+) in 3, whereas conventional surgical assessment of MR by fluid filling of the arrested ventricle failed to provide reliable differentiation. MR severity on subsequent closed-chest color Doppler follow-up did not change significantly compared with intraoperative evaluation after repair. Intraoperative color Doppler provides accurate grading of MR severity, offers instantaneous evaluation of the adequacy of mitral valve repair before chest closure, and appears to predict the degree of postoperative MR seen on subsequent closed-chest follow-up studies.

Morbidity and mortality after coronary artery bypass in octogenarians.

One hundred fifty seven consecutive octogenarians (mean age +/- standard deviation, 82.4 +/- 1.9 years) underwent coronary artery bypass grafting with hypothermia (mean temperature, 21.8 degrees +/- 1.8 degrees C), hyperkalemic cardioplegia, and cardiopulmonary bypass in a 9-year period. Sixty-six percent were male. Preoperatively, 115 patients (73%) were in New York Heart Association functional class IV, with the remainder being in either class III (23%) or class II (4%). Twenty percent of the patients had major complications including postoperative hemorrhage (15), sepsis (9), cerebrovascular accident (6), third-degree heart block (5), renal failure requiring dialysis (1), and pulmonary embolism (1). The 30-day or in-hospital mortality rate was 7.0%. Mean total hospital stay was 26.1 +/- 17.9 days. One-year and 5-year actuarial survival rates were 85% and 62%, respectively. Higher mortality was seen to be associated with New York Heart Association class IV, left ventricular ejection fraction less than 0.40, and lesser values for cardiac output and cardiac index. At the 6-month postoperative follow-up, 73% of the survivors reported that their general health had improved as compared with before operation. This experience demonstrates that for select octogenarians with unmanageable angina pectoris, coronary artery bypass grafting is an effective therapeutic option.

Perivascular Delivery Of A Nitric Oxide Donor Inhibits Neointimal Hyperplasia In Vein Grafts Implanted In The Arterial Circulation

OBJECTIVE Nitric oxide has been reported to reduce intimal hyperplasia as a response to arterial injury. This study was designed to assess the possible effect of perivascular application of a nitric oxide donor on neointimal proliferation occurring in veins exposed to the dynamics of the arterial circulation in a hypercholesterolemic rabbit model. METHODS Autologous jugular vein grafts were implanted in the carotid circulation of 20 hypercholesterolemic rabbits. A mixture of a biodegradable polymer and the nitric oxide donor, spermine/nitric oxide, which releases nitric oxide with a half-life of 39 minutes, was applied periadventitially at the time of implantation. Controls were veins bathed in saline solution, polymer alone, and polymer plus the carrier vehicle spermine without nitric oxide. Animals (n = 5 in each group) were put to death on day 28 for morphometric analysis, cell count, and immunohistochemical staining. RESULTS Treatment with perivascular nitric oxide donor significantly decreased wall thickness (126 +/- 24 microm vs 208 +/- 45 microm, p = 0.0017) and area (124 +/- 22 microm2/microm vs 211 +/- 37 microm2/microm, p = 0.005). With the carrier vehicle spermine alone, there was a trend toward reduced intimal thickness, but the change was not statistically significant. In the grafts treated with nitric oxide donor, expression of insulin-like growth factor, fibroblast growth factor, thrombospondins, fibronectin, and tenascin was reduced. CONCLUSION The periadventitial delivery of nitric oxide donor produces a reduction of neointimal hyperplasia in veins implanted in the arterial circulation. The mechanism of action is not entirely clear, but the reduction cannot be explained on the basis of decreased cell proliferation alone. Other possibilities are modulation of protein synthesis of vascular smooth muscle cells and production of extracellular matrix components.

Combined Valve and Coronary Artery Bypass Procedures in Septuagenarians and Octogenarians: Results in 120 Patients

A consecutive series of 96 septuagenarians (mean age, 74) and 24 octogenarians (mean age, 83) underwent coronary artery bypass (CAB) and valve operations using hypothermia and hyperkalemic cardioplegia in a 45-month period; there was a mean of 2.6 grafts per patient. Most patients were in New York Heart Association (NYHA) class IV (57% of the septuagenarians and 88% of the octogenarians) preoperatively. The early deaths were 19% for septuagenarians and 37% for octogenarians; late deaths were 9% and 6%, respectively, after a mean of 25 months. Of 92 survivors, 78% of the septuagenarians and 87% of the octogenarians improved by one or more NYHA class postoperatively. Of 58 patients with combined CAB and aortic valve replacement, 12 (21%) died; of 38 with combined CAB and mitral valve replacement 19 (50%) died; 2 of 9 (22%) with combined CAB and double valve replacement died; and 2 of 11 (18%) with CAB and MV repair died. In comparison, of patients with isolated valve replacement in the same period, 2 of 30 (7%) in the AVR group died, 5 of 17 (29%) died in the MVR group, 2 of 7 (33%) in the DVR group died. The risk of combined valve procedures and bypass surgery was significantly increased in the elderly and may warrant a less aggressive procedure, especially in the mitral position.

The St. Jude Medical valve: Experience with 1000 cases

We analyzed the long-term results of valve replacement with the St. Jude Medical bileaflet valve (St. Jude Medical, Inc., St. Paul, Minn.) in our first 1000 implantations between 1978 and 1992. A total of 399 patients had mitral valve replacement, 471 aortic valve, and 130 double (mitral and aortic) valve replacement. The average patient age was 64 +/- 15 years and the majority of patients (52%) had concomitant coronary disease. With 4328 patient-years of follow-up, 83% of the mitral group, 76% of the aortic group, and 77% of the double valve group were free of thromboembolism at 10 years after operation, and 87% of the mitral group, 82% of the aortic group, and 85% of the double valve group were free of valve-related hemorrhage. At 10 years, 91% of the mitral group, 84% of the aortic group, and 84% of the double valve group were free of valve-related death. However, overall survival at 10 years was only 42% +/- 4% for the mitral group, 43% +/- 4% for the aortic group, and 43% +/- 6% for the double valve group. For all three groups, age was a highly significant factor stratifying survival (p < 0.001), as was the presence of coronary disease (all p < 0.001). The excellent freedom from valve-related death at 10 years of 84% to 91% is in striking contrast to the overall survivals of 42% to 43% at 10 years. This difference suggests that the primary factors limiting long-term survival after valve replacement with the St. Jude Medical valve are not valve-related factors, but other patient factors such as age and concomitant coronary disease.