Long-term clinical outcomes of the Toronto stentless porcine valve: 15-year results from dual centers.

BACKGROUND AND AIM OF THE STUDY: The purpose of this study is to examine the long-term durability of the Toronto stentless porcine valve (SPV) in the aortic position (St Jude Medical, Minneapolis, MN). METHODS: We assessed the long-term clinical outcomes of 515 patients with aortic valve replacement (AVR) with the Toronto SPV from 1987 to 2001 at two centers, excluding early (<30 days) death. Median follow-up was 11.5 years (maximum 19.0 years). RESULTS: Average age was 64.2 ± 10.8 years, and females were 34% (173/515). The incidence of prosthesis-patient mismatch was low, 10.9%. Overall survival was 90.7 ± 1.3%, 75.4 ± 2.0%, and 56.8 ± 3.2% at 5, 10, and 15 years, respectively after surgery. Over the follow-up duration, 116 patients (23%) underwent repeated AVR: 90 for structural valve deterioration (SVD), 12 for endocarditis, 10 nonstructural valve dysfunction (10 aortic regurgitation due to aorta dilatation), and four for other reasons. The cumulative incidence of repeated AVR with death as a competing risk was 1.4% (95% confidence interval [CI], 0.6-2.7), 11.1% (95% CI, 8.4-14.2), and 34.4% (95% CI, 28.8-40.2) at 5, 10, and 15 years, respectively. Reoperative mortality was 5.2% (6/116). In SVD, the regurgitation type was dominant (82%). CONCLUSIONS: The Toronto SPV is associated with excellent survival and durability during the first decade of follow-up. However, regurgitation type of SVD increases from 10 years after operation with acceptable reoperative mortality. These findings may assist with prosthesis selection and reintervention strategy for failing stentless bioprosthesis.

Are stentless valves hemodynamically superior to stented valves? Long-term follow-up of a randomized trial comparing Carpentier-Edwards pericardial valve with the Toronto Stentless Porcine Valve.

OBJECTIVE: The benefit of stentless valves remains in question. In 1999, a randomized trial comparing stentless and stented valves was unable to demonstrate any hemodynamic or clinical benefits at 1 year after implantation. This study reviews long-term outcomes of patients randomized in the aforementioned trial. METHODS: Between 1996 and 1999, 99 patients undergoing aortic valve replacement were randomized to receive either a stented Carpentier-Edwards pericardial valve (CE) (Edwards Lifesciences, Irvine, Calif) or a Toronto Stentless Porcine Valve (SPV) (St Jude Medical, Minneapolis, Minn). Among these, 38 patients were available for late echocardiographic follow-up (CE, n = 17; SPV, n = 21). Echocardiographic analysis was undertaken both at rest and with dobutamine stress, and functional status (Duke Activity Status Index) was compared at a mean of 9.3 years postoperatively (range, 7.5-11.1 years). Clinical follow-up was 82% complete at a mean of 10.3 years postoperatively (range, 7.5-12.2 years). RESULTS: Preoperative characteristics were similar between groups. Effective orifice areas increased in both groups over time. Although there were no differences in effective orifice areas at 1 year, at 9 years, effective orifice areas were significantly greater in the SPV group (CE, 1.49 +/- 0.59 cm(2); SPV, 2.00 +/- 0.53 cm(2); P = .011). Similarly, mean and peak gradients decreased in both groups over time; however, at 9 years, gradients were lower in the SPV group (mean: CE, 10.8 +/- 3.8 mm Hg; SPV, 7.8 +/- 4.8 mm Hg; P = .011; peak: CE, 20.4 +/- 6.5 mm Hg; SPV, 14.6 +/- 7.1 mm Hg; P = .022). Such differences were magnified with dobutamine stress (mean: CE, 22.7 +/- 6.1 mm Hg; SPV, 15.3 +/- 8.4 mm Hg; P = .008; peak: CE, 48.1 +/- 11.8 mm Hg; SPV, 30.8 +/- 17.7 mm Hg; P = .001). Ventricular mass regression occurred in both groups; however, no differences were demonstrated between groups either on echocardiographic, magnetic resonance imaging, or biochemical (plasma B-type [brain] natriuretic peptide) assessment (P = .74). Similarly, Duke Activity Status Index scores of functional status improved in both groups over time; however, no differences were noted between groups (CE, 27.5 +/- 19.1; SPV, 19.9 +/- 12.0; P = .69). Freedom from reoperation at 12 years was 92% +/- 5% in patients with CEs and 75% +/- 5% in patients with SPVs (P = .65). Freedom from valve-related morbidity at 12 years was 82% +/- 7% in patients with CEs and 55% +/- 7% in patients with SPVs (P = .05). Finally, 12-year actuarial survival was 35% +/- 7% in patients with CEs and 52% +/- 7% in patients with SPVs (P = .37). CONCLUSION: Although offering improved hemodynamic outcomes, the SPV did not afford superior mass regression or improved clinical outcomes up to 12 years after implantation.

Troponin after cardiac surgery: a predictor or a phenomenon?

BACKGROUND: Increased cardiac troponin is observed after virtually every cardiac operation, indicating perioperative myocardial injury. The clinical significance of this elevation is controversial. This study aimed to correlate postoperative troponin levels with major adverse cardiac events (MACE). METHODS: The study included 1918 consecutive patients undergoing adult cardiac operations, including 1515 isolated coronary procedures, 229 valvular operations, and 174 combined coronary/valve procedures. Peak troponin T (normal value < 0.1 microg/L) was measured at less than 24 hours postoperatively. Excluded were 506 patients with a recent myocardial infarction (< 30-days of operation). The primary outcome was a composite of death, electrocardiogram-defined infarction, and low output syndrome (MACE). RESULTS: Mortality rates were 1.4%, 6.1%, and 7% in the coronary bypass, valve, and combined groups, respectively (p < 0.001). The rates of MACE were 17%, 35%, and 44% (p < 0.0001), and mean troponin T levels were 0.9 +/- 1.5, 1.2 +/- 2.9, and 1.3 +/- 1.2 microg/L (p < 0.001), in the coronary bypass, valve, and combined groups, respectively. All patients were divided into quintiles based on their peak postoperative troponin level (Q1, 0.0 to 0.39; Q2, 0.4 to 0.59; Q3, 0.6 to 0.79; Q4, 0.8 to 1.29; and Q5, > 1.3 microg/L). Adverse outcomes were similar and stable in the lower quintiles. A stepwise increase in adverse outcomes was observed in the higher quintiles. Receiver operating characteristic curve analysis revealed a troponin cutoff of 0.8 microg/L was the most discriminatory for MACE (area under the curve, 0.7). Multivariable analyses showed a troponin value of more than 0.8 microg/L was independently associated with MACE. CONCLUSIONS: Moderate elevations in troponin are common after cardiac operations; troponin is a well-described predictor of outcomes. Troponin levels exceeding 0.8 microg/L are associated with increased MACE in patients without a history of preoperative myocardial infarction within 30 days of operation.

The life and hard times of a coronary surgeon.

Coronary artery bypass is arguably the most extensively studied operation in surgical history. The technical advances and beneficial effects on symptoms and prognosis have been well documented over four decades. Percutaneous coronary interventions (PCIs) have also evolved through numerous modifications, and symptom relief has been substantiated; both modalities have been challenged by many randomized controlled trials. The rapid growth of PCIs has decreased coronary artery bypass volumes, and resulted in concerns about training, teaching, research, jobs and income. The most important concern, however, is the increasing 'off-label' application of PCIs with drug-eluting stents to a variety of untested coronary lesions. The randomized controlled trials studied a small fraction of those registered and excluded patients who are known to benefit from surgery and, thus, these studies were inherently biased. The results were then extrapolated to 'real-world' patients, who had been misinformed and misled about the performance and prognosis of coronary stents, as was later revealed in various registries. Hospitals should develop a collaborative revascularization strategy to provide patients and families with realistic alternatives.

A randomized comparison of intraoperative indocyanine green angiography and transit-time flow measurement to detect technical errors in coronary bypass grafts.

BACKGROUND: Early coronary bypass graft failures may be preventable if identified intraoperatively. The purpose of this investigation was to compare the diagnostic accuracy of two intraoperative graft assessment techniques, transit-time ultrasound flow measurement and indocyanine green fluorescent-dye graft angiography. METHODS: Patents undergoing isolated coronary artery bypass grafting with no contraindications for postoperative angiography were enrolled in the study. Patients were randomly assigned to be evaluated with either indocyanine green angiography (Novadaq Spy angiography system; Novadaq Technologies Inc, Concord, Ontario, Canada) and then transit-time ultrasonic flow measurement (Medtronic Medi-Stim Butterfly Flowmeter TTF measurement system; Medtronic Inc, Minneapolis, Minn) or transit-time flow then indocyanine green angiography. Patients underwent x-ray angiography on postoperative day 4. The primary end point of the trial was to determine the sensitivity and specificity of the two techniques versus reference standard x-ray angiography to detect graft occlusion or greater than 50% stenosis in the graft or perianastomotic area. RESULTS: Between February 2004 and March 2005, 106 patients were enrolled and x-ray angiography was performed in 46 patients. In total, 139 grafts were reviewed with all three techniques and 12 grafts (8.2%) were demonstrated to have greater than 50% stenosis or occlusion by the reference standard. The sensitivity and specificity of indocyanine green angiography to detect greater than 50% stenosis or occlusion was 83.3% and 100%, respectively. The sensitivity and specificity of transit-time ultrasonic flow measurement to detect greater than 50% stenosis or occlusion was 25% and 98.4%, respectively. The P value for the overall comparison of sensitivity and specificity between indocyanine green angiography and transit-time flow ultrasonography was .011. The difference between sensitivity for indocyanine green angiography and transit-time flow measurement was 58% with a 95% confidence interval of 30% to 86%, P = .023. CONCLUSION: Indocyanine green angiography provides better diagnostic accuracy for detecting clinically significant graft errors than does transit-time ultrasound flow measurement.

Improving the quality of coronary bypass surgery with intraoperative angiography: validation of a new technique.

OBJECTIVES: We report a comprehensive assessment and validation of a new intraoperative angiography technique. BACKGROUND: Technical problems at the site of the distal anastomosis compromise an underappreciated proportion of coronary bypass grafts. The absence of a systematic, validated technique to verify graft patency in the operating room represents a significant breach in quality assurance. METHODS: Fluorescent indocyanine green (ICG) dye is excited with dispersed laser light to create an angiographic depiction of the graft, native vessel, and anastomosis. One-hundred twenty patients underwent ICG angiography. Angiograms were reviewed for reliability and validity studies. RESULTS: A total of 348 coronary bypass grafts were studied. Each ICG angiogram took 2.2 +/- 1.1 min to perform. The ICG angiography found 4.2% of patients had significant graft problems requiring major revision. Quality of visualization was rated according to a seven-point Likert scale (1 = worst, 7 = best). Among conduits, saphenous veins were best visualized (mean score +/- standard deviation), 6.4 +/- 1.5 versus 5.5 +/- 1.9 for internal mammary arteries and 4.4 +/- 2.3 for radial arteries (p = 0.02). Location of distal anastomosis did not influence quality of visualization. There was high inter-rater reliability for graft revision (kappa = 1.0) and graft patency (kappa = 0.97) between surgeons. Sensitivity and specificity of the ICG angiograms for graft stenosis >50% was 100% among 22 grafts also studied with X-ray angiography. CONCLUSIONS: Information from ICG angiograms led to graft revisions for technical problems in 4.2% of patients that would have otherwise gone unrecognized. Intraoperative angiography is an emerging tool for improving the quality of coronary bypass surgery.

Determinants of incomplete left ventricular mass regression following aortic valve replacement for aortic stenosis.

OBJECTIVE: Incomplete regression of left ventricular hypertrophy (Abn-LVMI) following AVR for aortic stenosis (AS) may decrease long-term survival. In this prospective study, we identified the predictors of Abn-LVMI. METHODS: Between 1990 and 2000, 529 patients undergoing AVR for AS had clinical and hemodynamic data collected prospectively. Preoperative and annual postoperative transthoracic echos were employed to assess left ventricular mass index (LVMI) and hemodynamics. Abn-LVMI was defined as the 75th percentile of the lowest postoperative LVMI (>128 mg/m2, n = 133). All other patients were included in the normal regression group (N-LVMI). Univariate and multivariable logistic regression analyses were used to determine the predictors of Abn-LVMI. RESULTS: Preoperative hypertension, diabetes, coronary disease, valve size, mean postoperative gradients, effective orifice area, and patient-prosthesis mismatch (PPM, indexed EOA <0.60 cm2/m2) did not predict Abn-LVMI. By logistic regression the most important positive predictor of Abn-LVMI was the extent of preoperative LVMI, with an odds ratio of 37.5 (p < 0.0001). Survival (93.4 +/- 1.8% vs 94.8 +/- 2.3%, p = 0.90) and freedom from NYHA III-IV (75.0 +/- 3.7% vs 76.6 +/- 5.3%, p = 0.60) were similar for both groups at 7 years. CONCLUSIONS: Measures of valve hemodynamics were not important predictors of incomplete regression of hypertrophy. The extent of preoperative hypertrophy was the most important predictor, suggesting that earlier surgical intervention may reduce the extent of hypertrophy postoperatively. Furthermore, the significance of LV hypertrophy to long-term survival must be reassessed, in the absence of scientific evidence.

Long-term results of aortic valve replacement with the St. Jude Toronto stentless porcine valve.

BACKGROUND: Long-term survival and freedom from valve-related events of the St. Jude Toronto stentless porcine valve (SPV) are unknown. The aim of this study was to investigate late clinical outcomes after aortic valve replacement with the Toronto SPV. METHODS: Between 1992 and 2000, 200 patients (131 males, 69 females) underwent aortic valve replacement with the Toronto SPV. Mean patient age at implantation was 64.6 +/- 10.9 years (range 33 to 82 years). At the time of operation, 32%, 51%, and 17% of patients were in New York Heart Association class I/II, III, and IV, respectively. Aortic stenosis, aortic insufficiency, and combined lesions were present in 64%, 13.5%, and 22.5% of patients preoperatively. Concomitant coronary artery bypass grafting was performed in 34.5% of patients. RESULTS: Perioperative mortality occurred in 2.5% (5/200) of patients. There were 31 late deaths. Actuarial survival at 5 and 10 years was 89.2% and 68.0%, respectively. There was no significant difference in overall actuarial survival between isolated valve patients and valve plus coronary artery bypass grafting patients, 71% versus 62% respectively, p = 0.85. Actuarial freedom from valve reoperation at 5 and 10 years was 97.6% and 79.9%, respectively. Actuarial freedom from structural valve deterioration was 98.8% at 5 years and declined to 77.9% at 10 years. Freedom from structural valve deterioration was poorer in patients with preoperative aortic insufficiency or bicuspid disease. Actuarial freedom from embolic events and endocarditis at 10 years were 94.6% and 95.9%, respectively. CONCLUSIONS: Although early clinical results were excellent, a significant increase in hazard for structural valve deterioration occurred in late follow-up.

Contemporary trends in aortic valve surgery: a single centre 10-year clinical experience.

The purpose of this study is to present a comprehensive profile of the trends in aortic valve replacement at a single institution over the past decade. Prospectively collected data concerning 873 patients undergoing aortic valve replacement (AVR), with and without coronary artery bypass grafting (CABG), were analysed. The patients were divided into three time periods: period I, (1990 to 1993); period II, (1994 to 1996); and period III, (1997 to 2000). Actuarial survival of AVR patients with and without CABG at 7 years was 82.9 +/- 2.4% and 79.1 +/- 3.3% (p = 0.17), respectively. Actuarial survival at 7 years for stentless, mechanical, and stented valve patients were 89.5 +/- 2.7%, 85.5 +/- 2.8%, and 76.0 +/- 3.2%, respectively. There was a significant difference in survival between the stentless and stented valve groups (p = 0.014). Age (63.8 +/- 12.9 yrs, 66.2 +/- 11.0 yrs, 67.9 +/- 10.3 yrs; p = 0.01), the incidence of peripheral vascular disease (5.1%, 10.8%, 16.6%; p = 0.001), and the extent of coronary artery disease necessitating CABG (34.0%, 38.8%, 41.0%; p = 0.05) have increased significantly in the later time period. However, operative mortality has remained constant (4.7%, 4.8%, 4.5%; p = 0.9). Moreover, perioperative complications have decreased significantly (27.4%, 18.0, 16.0%; p = 0.001). Multivariate analysis identified more recent time period as independent protective factor for early mortality and morbidity (period I, RR 1.00; period II, RR 0.47; period III, RR 0.40).

Why is off-pump coronary surgery uncommon in Canada? Results of a population-based survey of Canadian heart surgeons.

BACKGROUND: Off-pump coronary artery bypass (OPCAB) is proposed to improve clinical outcomes and decrease resource use. However, off-pump surgery is not widely used in Canada. The purpose of this study was to determine the current use of OPCAB in Canada and determine why surgeons have not adopted this technique. METHODS AND RESULTS: The study was a population-based survey of all adult Canadian cardiac surgeons in practice >1 year. Eligible division heads and surgeons were contacted by mail. Of 19 806 isolated coronary bypass surgeries performed by respondents in Canada last year, 3164 (16.0%) were performed off-pump. More than 50% of Canadian surgeons performed OPCAB in <5% of coronary cases, and only 17% of surgeons performed OPCAB in >25% of coronary cases. Only 4 responding centers performed OPCAB in >25% of cases. Respondents were divided into those who performed <5% of cases off-pump (nonadopters), 5% to 25% off-pump (intermediate users), or >25% off-pump (enthusiasts). Mean number of distal anastomoses in off-pump cases were 1.7+/-0.6, 1.6+/-0.6, and 3.3+/-0.5 for nonadopters, intermediate users, and enthusiasts, respectively (P=0.001). Eleven percent of nonadopters, 55% of intermediate users, and 81% of enthusiasts believed OPCAB improved clinical outcomes (P<0.0001). Only 23% of all respondents felt OPCAB use would increase in the next 5 years. CONCLUSIONS: Concerns regarding incomplete revascularization and lack of proven clinical benefit have limited OPCAB to being performed routinely by only a small number of surgeons in Canada.

Late outcomes in patients with uncorrected mild to moderate mitral regurgitation at the time of isolated coronary artery bypass grafting.

OBJECTIVES: Patients undergoing coronary artery bypass grafting often have untreated mild to moderate mitral regurgitation. The long-term outcome of these patients follows an uncertain course. The purpose of this study was to examine the late outcomes in patients with mild to moderate mitral regurgitation at the time of isolated coronary artery bypass grafting. METHODS: One hundred sixty-three patients with mild to moderate mitral regurgitation at the time of isolated coronary artery bypass grafting were identified from the prospectively collected cardiovascular database at Sunnybrook and Women's College Health Sciences Centre. These patients were matched 1:2 with patients who had isolated coronary artery bypass grafting without mitral regurgitation according to gender, age, left ventricular ejection fraction, New York Heart Association functional class, vascular disease, diabetes, extent of coronary disease, and year of surgery. There was 99% complete follow-up. Actuarial survival and event-free (death, myocardial infarction, stroke, cardiac hospitalization, and cardiac reintervention) survivals were compared by log-rank methods. Cox regression was used to assess the effects of the presence of mitral regurgitation on late survival and event-free survival. Preliminary postoperative follow-up echocardiography was available for 49 of the 163 patients with mitral regurgitation. RESULTS: There were 489 patients in the matched-cohort study, 163 with mitral regurgitation and 326 without. The average length of follow-up was 3.37 +/- 2.04 years. There was no difference in actuarial survival at 6 postoperative years (mitral regurgitation 81.0% vs no mitral regurgitation 84.7%, P =.9185). Event-free survival at 6 years was worse in the mitral regurgitation group (45.7% vs no mitral regurgitation 64.7%, P =.0258). Patients with mitral regurgitation had worse functional status (New York Heart Association class 3-4 20.0%, n = 30/150, vs no mitral regurgitation 8.1%, n = 25/307, P =.0046). After the matched variables were controlled for, the hazard ratios associated with the presence of mitral regurgitation by Cox regression were 0.958 (P =.7626) for survival and 1.198 (P =.0333) for event-free survival. The only other significant predictor of late survival was preoperative intra-aortic balloon pump insertion (hazard ratio 2.484, P =.0365). Of the patients who underwent follow-up echocardiography, 30.6% (n = 15/49) had progression of mitral regurgitation to moderate to severe degree at an average of 16.4 postoperative months. CONCLUSION: Overall late survival was not affected by the presence of mild to moderate degrees of mitral regurgitation in patients undergoing coronary artery bypass grafting. However, these patients had poorer event-free survival and worse late functional status. In a subset of patients with echocardiographic follow-up, the postoperative course of mitral regurgitation was variable, and nearly a third of these patients had worsening mitral regurgitation. Consideration should be given to repairing moderate mitral regurgitation in selected cases to improve long-term quality of life.

Radial artery use is safe in patients with moderate to severe left ventricular dysfunction.

BACKGROUND: Using radial artery grafts in patients with moderate to severe left ventricular dysfunction (LVD; ejection fraction < 35%) has been discouraged for the fear that postoperative vasopressor support may cause graft spasm and lead to ischemic complications. We, therefore, examined the safety of radial grafts in aortocoronary bypass (ACB) patients with LVD. METHODS: Data were collected from 5,455 patients who underwent isolated ACB between January 1995 and September 2001. One thousand eight hundred three patients received a radial artery graft (RadACB), and 3,652 patients did not (NoRadACB). Three hundred seven RadACB, and 819 NoRadACB operations were performed in LVD patients. A matched (age, sex, urgency of operation, diabetes, and renal insufficiency) cohort analysis was performed in LVD patients. Univariate and logistic regression analyses were performed in the entire population and the unmatched RadACB and NoRadACB patient subgroups to examine the effect of radial artery use on postoperative death or myocardial infarction rate. RESULTS: The matched cohort analysis revealed a similar rate of death or myocardial infarction (RadACB, 11 of 242 patients; NoRadACB, 16 of 242 patients; p = 0.32). Left ventricular dysfunction was associated with a higher rate of death or myocardial infarction in both unmatched groups (RadACB, odds ratio, 2.36; 95% confidence interval, 1.38 to 4.58; p = 0.004; NoRadACB, odds ratio, 1.62; 95% confidence interval, 1.18 to 2.24; p < 0.001) and in the entire population (odds ratio, 1.77; 95% confidence interval, 1.32 to 2.35; p = 0.003). An interaction term for patients with LVD and a radial artery graft, which was forced into the logistic regression model for the entire population, was not predictive of death or myocardial infarction (odds ratio, 1.52; 95% confidence interval, 0.75 to 3.10; p = 0.25). CONCLUSIONS: Left ventricular dysfunction carries similar risk for postoperative death or myocardial infarction in RadACB and NoRadACB patients. The presence of LVD in isolation is not a contraindication to the use of radial grafting.

The influence of cardiopulmonary bypass flow characteristics on the clinical outcome of 1820 coronary bypass patients.

OBJECTIVE: To determine whether pulsatile perfusion is clinically beneficial for adult cardiac operations. METHODS: Data concerning consecutive patients undergoing isolated coronary bypass surgery (n=1820) from January 1, 1997 to July 31, 1999 were reviewed. RESULTS: Nine hundred fifteen patients received pulsatile perfusion (PP) while perfusion in the remaining 905 patients was nonpulsatile (NP). Patients in the PP group were older (64.0 +/- 9.2 years versus 63.1 +/- 9.9 years) and experienced more of the following: urgent operations (42.4% versus 38.0%), preoperative intra-aortic balloon pump (4.8% versus 1.8%), preoperative cerebrovascular accidents (CVA; 3.1% versus 1.3%) and renal insufficiency (10.5% versus 7.0%). The PP group had higher incidence of early postoperative mortality (2.6% versus 1.5%), CVA (3.1% versus 1.3%), need for dialysis (3.2% versus 2.2%) and longer hospital stay (9.2 +/- 8.3 days versus 8.5 +/- 5.8 days). The incidence of postoperative myocardial infarction and renal dysfunction was similar in both groups (2.0% versus 2.2% and 3.3% versus 3.9% respectively; not significant). Because of the significant difference in preoperative parameters for the PP and NP groups, the following three statistical techniques were used to isolate the effect of perfusion characteristics on operative outcome: multiple regression, propensity score and risk stratification. Multivariate analysis did not find PP to be protective against mortality, morbidity and mortality, and CVA or for the development of postoperative renal dysfunction. When propensity score analysis was applied, the incidence of cardiac morbidity and mortality was strongly associated with the quintile (first quintile 6.7%, fifth quintile 27.0%, P<0.001). Multivariate analysis including quintiles did not find PP to be an independent predictor for mortality or for morbidity and mortality. Risk stratification was performed for age and for preoperative creatinine clearance levels. In all groups, PP did not seem to reduce the incidence of morbidity, morbidity and mortality, or the development of postoperative renal dysfunction. In patients with preoperative renal dysfunction, mean postoperative creatinine levels and the need for dialysis following surgery were similar in the PP and NP groups. CONCLUSION: Pulsatile flow does not appear to offer any clinical benefit over nonpulsatile flow for cardiac surgery patients.

The short-term and long-term effects of warm or tepid cardioplegia.

BACKGROUND: Clinical studies of myocardial protection rarely identify differences in hard clinical outcomes after surgery, either early or late, because most trials lack sufficient statistical power to deal with low-frequency events. METHODS: Prospectively collected data concerning all isolated coronary bypass operations from November 1989 to February 2000 were analyzed to determine the effects of cold blood cardioplegia and warm or tepid blood cardioplegia on early and late outcomes after surgery. Warm blood cardioplegia was used in 4532 patients, whereas cold blood cardioplegia was used in 1532. The allocation of patients to receive warm blood cardioplegia and cold blood cardioplegia was random in 749 cases and according to surgeon preference in the remainder. Most patients in the cold blood cardioplegia group had surgery earlier in the time course of the study, and most in the warm blood cardioplegia group underwent surgery later. RESULTS: Perioperative death, myocardial infarction, and death or myocardial infarction were all more common in the cold blood cardioplegia group than in the warm blood cardioplegia group (death 2.5% vs 1.6%, P =.027, adjusted odds ratio 1.45, 95% confidence interval 0.95-2.22, P =.09; myocardial infarction 5.4% vs 2.4%, P <.0001, adjusted odds ratio 1.86, 95% confidence interval 1.36-2.53, P <.0001; death or myocardial infarction 7.3% vs. 3.8%, P <.0001, adjusted odds ratio 1.70, 95% confidence interval 1.30-2.21, P <.0001). Actuarial survival at 60 months was 91.1% +/- 1.4% in the warm blood cardioplegia group and 89.9% +/- 1.3% in the cold blood cardioplegia group (P =.09), whereas freedom from death or myocardial infarction was 84.7% +/- 1.8% and 83.2% +/- 1.6%, respectively (P =.16). In multivariate models, cold blood cardioplegia was associated with poorer survival (risk ratio 1.30, 95% confidence interval 0.96-1.75, P =.09) and freedom from any death or late myocardial infarction (risk ratio 1.93, 95% confidence interval 1.56-2.39, P =.0001). CONCLUSIONS: In 6064 patients undergoing isolated coronary artery bypass grafting, warm or tepid blood cardioplegia may be associated with better early and late event-free survivals than is cold cardioplegia.

Patient prosthesis mismatch is rare after aortic valve replacement: valve size may be irrelevant.

BACKGROUND: Although small valve size and patient-prosthesis mismatch are both considered to decrease long-term survival, little direct evidence exists to support this hypothesis. METHODS: To assess the prevalence of patient-prosthesis mismatch and the influence of small valve size on survival, we prospectively studied 1,129 consecutive patients undergoing aortic valve replacement between 1990 and 2000. Mean and peak gradients and indexed effective orifice area were measured by transthoracic echocardiography postoperatively (3 months to 10 years). Abnormal postoperative gradients were defined as those patients with mean or peak gradient above the 90th percentile (mean gradient > or = 21 or peak gradient > or = 38 mm Hg). Patient-prosthesis mismatch was defined as those patients with indexed effective orifice area below the 10th percentile (< 0.60 cm2/m2). RESULTS: A multivariable analysis identified internal diameter of the implanted valve as the only independent predictor of abnormal gradients postoperatively. However, there was no significant difference in actuarial survival between normal and abnormal gradient groups (7 years: 91.2% +/- 1.5% versus 95.0% +/- 2.2%; p = 0.48). Freedom from New York Heart Association class III or IV (7 years: 74.5% +/- 3.1% versus 74.6% +/- 6.2%; p = 0.66) and left ventricular mass index were not different between normal and abnormal gradient groups. Patients with and without patient-prosthesis mismatch were similar with respect to postoperative left ventricular mass index, 7-year survival (95.1% +/- 1.3% versus 94.7% +/- 3.0%; p = 0.54), and 7-year freedom from New York Heart Association class III or IV (79.3% +/- 6.6% versus 74.5% +/- 2.5%; p = 0.40). In patients with patient-prosthesis mismatch and abnormal gradients, the majority had prosthesis dysfunction owing to degeneration. CONCLUSIONS: Severe patient-prosthesis mismatch is rare after aortic valve replacement. Patient-prosthesis mismatch, abnormal gradient, and the size of valve implanted do not influence left ventricular mass index or intermediate-term survival.