James G. Abel

Usefulness of Coronary Stenting for Cardiogenic Shock

Coronary stenting was performed in 15 selected patients with cardiogenic shock, with favorable clinical and angiographic outcomes. This experience suggests that coronary stenting may play an important adjunctive role in the management of cardiogenic shock and may improve outcome beyond that achieved with balloon angioplasty alone.

Medtronic Mosaic porcine bioprosthesis: Satisfactory early clinical performance

BACKGROUND The Medtronic (Minneapolis, MN) Mosaic porcine bioprosthesis is an investigational prosthesis which incorporates zero-pressure fixation, aortic root predilation, low profile stent, and alpha oleic acid antimineralization treatment. METHODS From September 1994 to August 1996, 289 patients (mean age 70 years, range, 28 to 88 years) had 227 (78.5%) aortic valve replacements and 62 (21.5%) mitral valve replacements. Concomitant procedures were performed in 61.2% (139) of aortic valve replacements and 54.8% (34) of mitral valve replacements. Of the aortic valve replacement group 70 (30.8%) were in the 61 to 70 age group and 134 (59.0%) were 71 years or older. Of the mitral valve replacements, 23 (37.1%) were 61 to 70 years and 30 (48.4%) 71 years or older. RESULTS The early mortality, overall, was 4.2% (12 of 289); for aortic valve replacement it was 4.0% (9) and for mitral valve replacement it was 4.8% (3). The late mortality for aortic valve replacement was 2.6% per patient-year (3 events, 1.3% of total) and for mitral valve replacement it was 3.3% per patient-year (one event, 1.6% of total). The reoperative rate for aortic valve replacement was 3.0% per patient-year (4), while there were no mitral valve replacement reoperations. The freedom from major thromboembolism was 97.3%+/-1.6% for aortic valve replacement and 94.7%+/-3.0% for mitral valve replacement at 1 to 1.5 years. The freedom from reoperation was 96.7%+/-1.7% for aortic valve replacement; there was no reoperation for mitral valve replacement. There were no cases of structural valve deterioration. In the aortic position the mean systolic gradient was low, approximately 11 mm Hg, across all sizes (range 8 to 12 mm Hg at 3 months and 10 to 13 mm Hg at 12 months). In the mitral position the mean diastolic gradient was approximately 5 mm Hg (range, 2 to 6 mm Hg) for all sizes 25 to 31 mm at the early and 1 year follow-up echocardiographic assessment. CONCLUSIONS The early clinical performance and in vivo hemodynamics are encouraging.

Effect of Immunosuppressive Therapy, Serum Creatinine, and Time After Transplant on Plasma Total Homocysteine in Patients Following Heart Transplantation

OBJECTIVES To determine the prevalence of hyperhomocysteinemia in heart transplant recipients, and to assess the effect of renal function and immunosuppressive medication on total plasma homocysteine (tHcy) levels. BACKGROUND Elevated plasma tHcy levels have been associated with increased risk of mortality in patients with established coronary artery disease. Graft coronary disease is the major cause of morbidity and mortality in long-term survivors of heart transplantation. The tHcy has been found to be elevated in heart and kidney transplant patients, however, the etiologic factors have not been clearly delineated. METHODS The study group consisted of 70 heart transplant recipients (56 males, 14 females, mean age 53+/-13 years [range 17 to 69 years]). The parameters evaluated were fasting tHcy level, cumulative cyclosporine (CyA) dose, cumulative prednisone dose, serum creatinine, and time from transplantation. RESULTS The mean fasting tHcy level was 20.5+/-10.2 micromol/L (range 5.2 to 59.0 micromol/L). Sixty-one (87%) had fasting tHcy levels greater than the seventy-fifth percentile of the general population (>12.2 micromol/L in males, and >10.1 micromol/L in females). There was no difference in mean post-transplant tHcy level between patients with and without coronary artery disease before transplantation (21.0+/-11.4 vs. 19.3+/-6.7 micromol/L, p = NS). There were significant relationships between the tHcy level and the serum creatinine (r = 0.76, p<0.001), and cumulative exposure to CyA (r = 0.31, p<0.01). There were no significant relationships between tHcy levels and cumulative prednisone dose, or time from transplantation. CONCLUSIONS Fasting tHcy levels are markedly elevated in the majority of patients following heart transplantation, and are correlated to serum creatinine. Further studies are needed to determine other etiologic factors of elevated tHcy following heart transplantation, and to examine the impact of elevated tHcy on clinical outcomes.

Clinical performance of biological and mechanical prostheses

Prosthetic valve replacement remains the most viable alternative for the treatment of severely diseased heart valves. The cumulative experience of mechanical protheses and bioprostheses was evaluated for a 10-year performance comparison: Carpentier-Edwards standard porcine bioprosthesis (CE-S), 1,214 operations; Carpentier-Edwards supraannular porcine bioprosthesis (CE-SAV), 2,489; and mechanical prostheses, 1,364 operations (St. Jude Medical, Carbomedics, Duromedics, and Björk-Shiley Monostrut). The freedom from thromboembolism and hemorrhage at 10 years was 82% for CE-S, 78% for CE-SAV, and 65% for mechanical prostheses (p < 0.05). The relationship existed for major thromboembolism and hemorrhage, 91% (CE-S), 87% (CE-SAV), and 88% (mechanical) (p < 0.05), without clinical relevance. The freedom from structural valve deterioration and valve-related reoperation favored mechanical prostheses (p < 0.05) at 10 years (structural failure: 78% for CE-S, 81% for CE-SAV, and 99% for the mechanical group; reoperation: 74% for CE-S, 76% for CE-SAV, and 88% for mechanical prostheses). The freedom from fatal reoperation was not clinically different: 96% for CE-S, 99% for CE-SAV, and 99% for mechanical prostheses (p < 0.05) at 10 years. The freedom from valve-related mortality was not different (p = not significant) at 10 years: 87% for CE-S; 92% for CE-SAV; and 91% for mechanical. The freedom from permanent impairment or residual morbidity, primarily from thromboembolism, was 95% for CE-S, 92% for CE-SAV, and 95% for mechanical group (p < 0.05) but not clinically relevant.(ABSTRACT TRUNCATED AT 250 WORDS)

Reliability audit of a regional cardiac surgery registry

OBJECTIVE The British Columbia Provincial Cardiac Registry collects demographic and clinical data on all patients who undergo cardiac surgery procedures in the province. The purpose of this study was to compare the reliability of data contained in Registry with data contained in hospital charts. METHODS Registry and hospital charts were compared for 480 cases. Thirty cases were randomly selected for the provinces 16 cardiac surgeons. For each case, 10 distinct fields were selected for analysis and classified as consistent, inconsistent, or rejected (data unavailable in one or other source). RESULTS The overall rate of consistency between charts and the Registry was 86.4%, with an inconsistency rate of 9.9% and a rejection rate of 3.7%. Consistency rates varied significantly across the 10 fields and among the 16 surgeons. Pairwise comparisons of rates between fields indicated that specific field types were problematic and should be targeted for improvement. In addition, pairwise comparisons of rates between surgeons indicated that further education on Registry use is required. CONCLUSIONS Recommendations for database design and management include provision of standard definitions for all fields; education of users; extension of the number of mandatory fields; revision of check-off box fields to yes/no/unsure fields; and collection of data close to the time that it is generated.

Neurological Outcomes and Cardiopulmonary Temperature: A Clinical Review

All available controlled studies of warm versus cold and antegrade versus retrograde delivery of cardioplegia were reviewed to assess the incidence of perioperative stroke and adverse neuropsychological outcomes. Nine randomized trials and substudies and two studies with immediate historical consecutive controls reported neurological outcomes and were described as warm versus cold. Pooled event rates for perioperative stroke were 1.5% for warm antegrade, 3.14% for warm retrograde, 1.7% for cold antegrade, and 0% to 1.2% for cold retrograde. Examining within trial differences, only one study showed a significant disadvantage to warm 4.5% versus cold 1.4% on incidence of perioperative stroke, but the design does not permit determination of whether the difference is due to systemic temperature, retrograde coronary perfusion, or other factors. Furthermore, if only warm (> 33°C) versus cold (< 30°C) systemic perfusion is examined in all studies for the incidence of stroke irrespective of cardioplegia temperature or antegrade versus retrograde coronary perfusion (warm 2.1%; cold 1.6%), the above study remains a significant outlier. This suggests that the differences found are unlikely to be due to temperature but may be related to antegrade versus retrograde coronary perfusion. Review of randomized trials evaluating neuropsychological function post‐cardiopulmonary bypass (post‐CPB) also failed to reveal any advantage related to temperature of systemic perfusion. Since manipulations that are most likely to give rise to cerebral embolization are uniformly carried out at normothermia at the beginning and end of the operation, it is not entirely unexpected that the incidence of neurological events was found to be independent of the temperature of CPB. Because stroke is both too rare and too variable in magnitude by chance alone, no studies to date have adequately assessed stroke severity in relation to systemic perfusion temperature or mode and route of cardioplegia delivery.

Effective treatment of hyperhomocysteinemia in heart transplant recipients with and without renal failure

BACKGROUND Elevated total plasma homocysteine (tHcy) levels have been associated with vascular disease and higher mortality in patients with coronary artery disease. Graft coronary disease is a major cause of mortality in long-term survivors of heart transplantation, and hyperhomocysteinemia may be one of its causes. The objectives of our study were to establish the effectiveness of a 3 stage homocysteine-lowering algorithm in a group of 84 heart transplant (HTx) patients and to evaluate the effect of renal function on the response to homocysteine-lowering therapy. METHODS Prospective treatment of 84 Htx patients (64 male; mean age, 48 +/- 13 years) with tHcy > 75th percentile consisted of a 3-stage treatment algorithm: Stage 1, folic acid (FA) 2 mg + vitamin (vit) B(12) 500 mcg daily; Stage 2, addition of vit B(6) 100 mg daily; Stage 3, increase FA to 15 mg daily. Serum creatinine (Cr) and tHcy levels were measured before treatment and 21 +/- 19 weeks after each stage of treatment. RESULTS All 3 stages of treatment significantly lowered mean tHcy from 22.4 +/- 16.3 (mean +/- SD) micromol/liter to 16.3 +/- 6.7 micromol/liter (p < 0.00001), from 17.6 +/- 6.1 micromol/liter to 15.2 +/- 5.3 micromol/liter (p < 0.0001), and from 16.8 +/- 5.2 micromol/liter to 15.6 +/- 5.3 micromol/liter (p < 0.05), respectively. The average reduction from baseline was 38%. Creatinine levels did not change significantly during the study period. Total plasma homocysteine levels decreased below the 75th percentile in 55% of patients, with Cr levels significantly lower in this group of patients (126 +/- 36 micromol/liter vs 182 +/- 65 micromol/liter, p < 0.00001). However, we found no significant relationship between % change in tHcy and baseline Cr. CONCLUSIONS In a group of 84 heart transplant patients with tHcy levels >75th percentile, treatment with FA and vit B(6) and B(12) according to a 3-stage algorithm resulted in statistically significant declines in mean tHcy levels. Overall, tHcy levels decreased 38%, with target tHcy levels <75th percentile achieved in 55% of the patients. The % change in tHcy was not related to Cr. Further studies are needed to correlate treatment of hyperhomocysteinemia with clinical endpoints, such as the time to development of transplant vasculopathy and long-term survival, and to define the most appropriate targets for therapy.

Seven-year results with the St Jude Medical Silzone mechanical prosthesis

OBJECTIVE The Artificial Valve Endocarditis Reduction Trial was stopped on January 21, 2000, due to a higher incidence of paraprosthetic leak in the St Jude Medical Silzone prosthesis compared with the conventional prosthesis. The Artificial Valve Endocarditis Reduction Trial investigators reported the 2-year results in 2002. This retrospective study assessed the influence on thromboembolism and paraprosthetic leak to 7 years. METHODS A total of 253 patients had 254 operations: 80 aortic valve replacements, 139 mitral valve replacements, and 35 multiple replacements with placement of Silzone prostheses. The mean age was 58.6 years (range 21-84 years, median age 59.8 years), and there were 126 women (49.8%) and 74 concomitant procedures (coronary artery bypass 28.9%). RESULTS Major paraprosthetic leak (repair, re-replacement, or mortality) occurred in 10 of the original procedures after 30 days (3 aortic valve replacements, 3 mitral valve replacements, 4 multiple replacements). Nine occurrences in 8 patients-5 early (<or=2 years) and 4 late (>2 years)-were managed. Seven were managed with definitive re-replacement. One was an early nonoperative fatality. There was 1 late fatality after the second late paraprosthetic leak reoperation. One of the 10 procedures occurring after 2 years had mild to moderate aortic valve replacement paraprosthetic leak managed as an incidental re-replacement at the time of correction of supra valvular patch stenosis. One additional occurrence, in addition to the 8 patients (<30 days), was considered a technical error and not related to the Silzone prosthesis and was replaced with a Silzone prosthesis. The linearized rate of paraprosthetic leak within the first 2 years of follow-up was 1.3%/patient-year and after 2 years was 0.4%/patient-year. The linearized occurrence rate for major thromboembolism was 0.42%/patient-year for aortic valve replacement and 1.71%/patient-year for mitral valve replacement. CONCLUSIONS Paraprosthetic leak with the St Jude Medical Silzone prosthesis was managed both during the early (<or=2 years) and late (>2years) intervals with re-replacement. Late managed events may be manifestations of earlier occurring paraprosthetic leak. Follow-up echocardiograms should meet standards of care, 6 to 12 months after surgery and at the slightest suspicion of dysfunction. There is no advanced continuing risk of the St Jude Medical Silzone prosthesis.

Long-term Outcomes of Multiple Arterial Coronary Artery Bypass Grafting: A Population-Based Study of Patients in British Columbia, Canada

Importance Although the long-term survival advantage of multiple arterial grafting (MAG) vs the standard use of left internal thoracic artery (LITA) supplemented by saphenous vein grafts (LITA+SVG) has been demonstrated in several observational studies, to our knowledge its safety and other long-term clinical benefits in a large, population-based cohort are unknown. Objective To compare the safety and long-term outcomes of MAG vs LITA+SVG among overall and selected subgroups of patients. Design, Setting, and Participants In this population-based observational study, we included 20 076 adult patients with triple-vessel or left-main disease who underwent primary isolated coronary artery bypass grafting (MAG, n = 5580; LITA+SVG, n = 14 496) in the province of British Columbia, Canada, from January 2000 to December 2014, with follow-up to December 2015. We performed propensity-score analyses by weighting and matching and multivariable Cox regression to minimize treatment selection bias. Exposures Multiple arterial grafting or LITA+SVG. Main Outcomes and Measures Mortality, repeated revascularization, myocardial infarction, heart failure, and stroke. Results Of 5580 participants who underwent MAG, 586 (11%) were women and the mean (SD) age was 60 (8.7) years. Of 14 496 participants who underwent LITA+SVG, 2803 (19%) were women and the mean (SD) age was 68 (8.9) years. The median (interquartile range) follow-up time was 9.1 (5.1-12.6) years and 8.1 (4.5-11.7) years for the groups receiving MAG and LITA+SVG, respectively. Compared with LITA+SVG, MAG was associated with reduced mortality rates (hazard ratio [HR], 0.79; 95% CI, 0.72-0.87) and repeated revascularization rates (HR, 0.74; 95% CI, 0.66-0.84) in 15-year follow-up and reduced incidences of myocardial infarction (HR, 0.63; 95% CI, 0.47-0.85) and heart failure (HR, 0.79; 95% CI, 0.64-0.98) in 7-year follow-up. The long-term benefits were coherent by all 3 statistical methods and persisted among patient subgroups with diabetes, obesity, moderately impaired ejection fraction, chronic obstructive pulmonary disease, peripheral vascular disease, or renal disease. Multiple arterial grafting was not associated with increased morbidity or mortality rates at 30 days overall or within patient subgroups. Conclusions and Relevance Compared with LITA+SVG, MAG is associated with reduced mortality, repeated revascularization, myocardial infarction, and heart failure among patients with multivessel disease who are undergoing coronary artery bypass grafting without increased mortality or other adverse events at 30 days. The long-term benefits consistently observed across multiple outcomes and subgroups support the consideration of MAG for a broader spectrum of patients who are undergoing coronary artery bypass grafting in routine practice.

A score to estimate 30-day mortality after intensive care admission after cardiac surgery

Objective: Several risk‐scoring systems have been developed to predict surgical mortality and complications in cardiac surgical patients, but none of the current systems include factors related to the intraoperative period. The purpose of this study was to develop a score that incorporates both preoperative and intraoperative factors so that it could be used for patients admitted to a cardiac surgical intensive care unit (ICU) immediately after surgery. Method: Preoperative and intraoperative data from 30,350 patients in four hospitals were used to build a multiple logistic regression model estimating 30‐day mortality after cardiac surgery. Sixty percent of the patients were used as a derivation group and forty percent as a validation group. Results: Mortality occurred in 2.6% of patients (n = 790). Preoperative factors identified in the model were age, female sex, emergency status, pulmonary hypertension, peripheral vascular disease, renal dysfunction, diabetes, peptic ulcer disease, history of alcohol abuse, and refusal of blood products. Intraoperative risk factors included the need for an intra‐aortic balloon pump, ventricular assist device or extracorporeal membrane oxygenation leaving the operating room, presence of any intraoperative complication reported by the surgeon, the use of inotropes, high‐dose vasopressors, red blood cell transfusion, and cardiopulmonary bypass time. When used after surgery at ICU admission, the model had C‐statistics of 0.86 in both derivation and validation sets to estimate the 30‐day mortality. Conclusions: Preoperative and intraoperative variables can be used on admission to a cardiac surgical ICU to estimate 30‐day mortality. The score could be used for risk stratification after cardiac surgery and evaluation of performance of cardiac surgical ICUs.