Sarpogrelate inhibits serotonin-induced proliferation of porcine coronary artery smooth muscle cells: implications for long-term graft patency.

BACKGROUND: Serotonin can induce proliferation of vascular smooth muscle cells. We assessed the ability of a specific serotonin receptor antagonist, sarpogrelate, to inhibit proliferation of cultured porcine coronary artery smooth muscle cells. METHODS: Cell proliferation and mitotic activity were measured using 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide. To determine the effect of sarpogrelate on DNA (deoxyribonucleic acid), RNA (ribonucleic acid), and protein synthesis, radioactive incorporation of 3H-thymidine, 3H-uridine, and 3H-phenylalanine, respectively, was used. Synthesis of DNA was also assessed by flow cytometry with propidium iodide as a fluorochrome. RESULTS: Serotonin, platelet-derived growth factor, endothelin, and angiotensin II all induced proliferation of porcine coronary artery smooth muscle cells. Sarpogrelate specifically inhibited the serotonin-induced cytokine trigger but did not influence platelet-derived growth factor-, endothelin-, or angiotensin II-induced cell proliferation. Sarpogrelate inhibited the serotonin-induced increase in intracellular free ionized calcium concentration, prevented mitogen-activated protein kinase activation, and down-regulated expression of the protooncogenes c-fos and c-jun. Sarpogrelate acted at the G1 phase of the cell cycle. CONCLUSIONS: These data suggest that sarpogrelate could be used as a therapeutic agent to inhibit serotonin-induced neointimal hyperplasia and improve patency of coronary artery bypass grafts.

A novel organ culture method to study intimal hyperplasia at the site of a coronary artery bypass anastomosis.

BACKGROUND: Intimal hyperplasia or restenosis at the site of a coronary artery bypass anastomosis contributes to early graft failure, and growth factor release in response to construction of the anastomotic site strongly influences this process. Due to the difficulties in studying restenosis after coronary artery bypass graft surgery, we have tested whether an organ culture model we have developed can simulate the early events associated with intimal hyperplasia. METHODS: End-to-side anastomosis of porcine radial artery to porcine coronary artery were constructed. The vessels were trimmed and incubated under standard tissue culture conditions for 14 days. Appropriate controls were treated similarly. The vessels were frozen, cryosectioned, and immunostained for the expression of the proliferation marker proliferating cell nuclear antigen (PCNA). A proliferative index (PCNA positive nuclei/total nuclei) was calculated for comparative purposes. RESULTS: Limited PCNA staining was observed in noncultured vessel segments (0.046+/-0.045). A slight increase in this index was observed in vessels that had been placed into culture without manipulation (0.230+/-0.141) and in vessels subjected to an arteriotomy (0.462+/-0.249). However, the most significant increase was obtained after construction of an anastomosis (4.98+/-6.66). No change in total cell number was evident over the course of the experiment or in relation to the treatment. CONCLUSIONS: Culture conditions and incision slightly stimulate cell proliferation in porcine coronary artery segments when compared with basal conditions of a native artery. In contrast, construction of an anastomosis increases proliferation 108-fold. Therefore, surgical manipulation of arterial conduits during construction of an anastomotic site is the primary trigger for intimal hyperplasia, independent of dissection and incision of the vessel. Furthermore, these data indicate the organ culture model we have developed will be useful for examining the cellular and molecular mechanisms that mediate intimal hyperplasia at the site of a coronary artery bypass graft anastomosis.

Does the use of a stentless bioprosthesis increase surgical risk?

Stentless aortic bioprostheses (SBPs) convey hemodynamic and perhaps survival benefit over stented counterparts. The aim of this study was to determine whether the more taxing operation increases surgical risk. We studied contemporary multicenter (USA) data submitted to the Food and Drug Administration (FDA) for Freestyle stentless (group I, n = 583) and Mosaic stented xenograft approval (group II, n = 1260). The study compared 30-day mortality for the two groups overall, then for isolated aortic valve replacement (AVR) and for AVR and coronary bypass (CABG). Because the USA Freestyle valves were used in selected patients (pts) we included SBP data (group III) from Oxford, where Freestyle valves were used consecutively within the same time frame. We also reviewed hospital mortality in the stentless bioprosthesis literature and compared this with the Society of Thoracic Surgery Database. There were no differences in age, NYHA, or incidence of CABG between the groups. There was no significant difference in operative mortality between stented (group II) and exclusive (group III) SBP patient groups (P =.233 for AVR and P =.478 for AVR + CABG), or between selective (group I) and exclusive (P =.929 for AVR and P =.390 for AVR + CABG) groups, after adjustment for risk factors. However, there was a significantly higher mortality both for isolated AVR (P =.026) and AVR + CABG (P =.001) in the selected stentless group compared with stented. This was partly attributed to greater mortality when the Freestyle was used in elderly patients by the full root replacement method, and to the higher proportion of females, and subjects with intra-aortic balloon pump insertion in this group. A meta-analysis of published stentless valve series, showed mortality rates to be lower than those of the STS National Database average. During the learning curve selective use of SBPs increased hospital mortality for AVR +/- CABG. Consecutive use dispelled the difference and the literature now suggests that SBPs may reduce hospital mortality for high-risk patients.

Midterm survival of stented versus stentless valves: does concomitant coronary artery bypass grafting impact survival?

The purpose of this study was to examine the impact of concomitant coronary artery bypass grafting (CABG) and valve design on survival following aortic valve replacement (AVR) with stentless and stented bioprostheses. Survival data for 1798 patients undergoing AVR between 1991 and 1997 with either a stentless (Medtronic Freestyle = 700, Toronto SPV = 447; N = 1147) or stented (Hancock II = 224, Carpentier-Edwards SAV = 427; N = 651) valve were analyzed. Bivariable analyses using Kaplan-Meier survival curves and log-rank test were performed to compare survival probabilities by valve type. Multivariable stepwise Cox's proportional hazard models were used to control for potentially confounding variables. Concomitant CABG was performed in 41% of stentless and 46% of stented patients (P =.04). Survival probability at 5 years was 0.84 (95% CI = 0.81, 0.87) for stentless versus 0.79 (95% CI = 0.75, 0.83) for stented patients (P =.004). In the absence of concomitant CABG, survival was superior in stentless (0.84) over stented (0.80) patients, but these differences were not statistically significant (P =.053). In patients that underwent AVR with concomitant CABG, survival was significantly better in stentless patients (0.82) than in stented individuals (0.77, P =.049). The unadjusted hazard ratio for stented versus stentless was 1.44 (95% CI = 1.12, 1.86, P =.005). In the final Cox's proportional hazard model the variables that effected survival were valve type and age in decades. New York Heart Association class at the time of surgery had a marginal effect on survival. The data demonstrate improved midterm survival with stentless versus stented valves. Subgroup analysis suggests survival benefits of stentless valves may be greater in patients who undergo concomitant CABG surgery.

Safety and efficacy of fast track in patients undergoing coronary artery bypass surgery.

BACKGROUND: The incidence of coronary artery bypass surgery has been increasing annually with increasing pressure on the health care system. Fast track has been proposed as a means to increase efficiency and volume, without an increase in hospital resources. To date this approach has not been critically assessed in Canada. METHODS: We examined 617 consecutive patients undergoing isolated CABG surgery. The patients were divided into (1) fast track (FT) recovery (n = 219), without admission to an ICU, and (2) non-fast track (NFT) recovery (n = 398) with direct admission to the ICU. There were no differences in age, gender, timing of surgery, left main stenosis, preoperative myocardial infarction, renal failure, diabetes, peripheral vascular disease, or in the incidence of chronic obstructive pulmonary disease between the two groups. The NFT group had a higher proportion of patients with NYHA Class III/IV symptoms preoperatively (65.7% vs. 57.3%, p = 0.048), in patients with an ejection fraction < 40% (42.5% vs. 30.6%, p = 0.004), or in the number of individuals with an IABP inserted before surgery (13 vs. 1, p < 0.001). RESULTS: In the FT group the average period of aortic occlusion (40.7 +/- 15.2 min vs. 71.8 +/- 26.5 min, p < 0.001) and perfusion time (67.8 +/- 24.5 min vs. 117.5 +/- 40.2 min, p < 0.001) were significantly less than in the NFT group. The number of grafts per patient was 3.3 +/- 1.0 vs. 3.2 +/- 1.0, respectively (p = 0.38). Operative mortality was 0.9% in the FT group and 1.3% in the NFT group (p = 1.0). Significant differences were seen in the proportion of patients that suffered from postoperative ventilatory failure (3.2% in FT vs. 12.1% in NFT, p < 0.001), and the proportion of patients that suffered any postoperative complication was significantly higher in the NFT group (21.4%) than in the FT group (9.1%, p < 0.001). The differences in postoperative complications resulted in a shorter length of stay (LOS) in FT patients (5.6 +/- 4.1 days vs. 9.7 +/- 9.4 days NFT, p < 0.001). Only 4.1% of patients that entered the FT group failed and required admission to the ICU. Multivariate stepwise logistic regression analysis identified non-fast track recovery as an independent predictor of morbidity in CABG surgery patients. CONCLUSIONS: The data indicate it is possible to perform isolated CABG surgery, in a large proportion of the population, without the need for admission to an ICU for postoperative care.

Off-pump surgery decreases postoperative complications and resource utilization in the elderly.

BACKGROUND: Bypass surgery in the elderly (age >70 years) has increased mortality and morbidity, which may be a consequence of cardiopulmonary bypass. We compare the outcomes of a cohort of elderly off-pump coronary artery bypass (OPCAB) patients with elderly conventional coronary artery bypass grafting (CABG) patients. METHODS: Chart and provincial cardiac care registry data were reviewed for 30 consecutive elderly OPCAB patients (age 74.7 +/- 4.2 years) and 60 consecutive CABG patients (age 74.9 +/- 4.1 years, p = 0.82) with similar risk factor profiles: Parsonnet score 17.2 +/- 8.1 (OPCAB) versus 15.6 +/- 6.5 (CABG), p = 0.31; and Ontario provincial acuity index 4.5 +/- 1.9 (OPCAB) versus 4.3 +/- 2.0 (CABG), p = 0.65. RESULTS: Mean hospital stay was 6.3 +/- 1.8 days for OPCAB patients and 7.7 +/- 3.9 days for CABG patients (p < 0.05). Average intensive care unit stay was 24.0 +/- 10.9 h for OPCAB patients versus 36.6 +/- 33.5 h for CABG patients (p < 0.05). Atrial fibrillation occurred in 10.0% of OPCAB patients and 28.3% of CABG patients (p < 0.05). Low output syndrome was observed in 10% of OPCAB patients and 31.7% of CABG patients (p < 0.05). Cost was reduced by $1,082 (Canadian) per patient in the OPCAB group. Postoperative OPCAB graft analysis showed 100% patency. CONCLUSIONS: OPCAB is safe in the geriatric population and significantly reduces postoperative morbidity and cost.

The role of donor age and ischemic time on survival following orthotopic heart transplantation.

BACKGROUND: The advances in immunotherapy, along with a liberalization of eligibility criteria have contributed significantly to the ever increasing demand for donor organs. In an attempt to expand the donor pool, transplant programs are now accepting older donors as well as donors from more remote areas. The purpose of this study is to determine the effect of donor age and organ ischemic time on survival following orthotopic heart transplantation (OHT). METHODS: From April 1981 to December 1996 372 adult patients underwent OHT at the University of Western Ontario. Cox proportional hazards models were used to identify predictors of outcome. Variables affecting survival were then entered into a stepwise logistic regression model to develop probability models for 30-day- and 1-year-mortality. RESULTS: The mean age of the recipient population was 45.6 +/- 12.3 years (range 18-64 years: 54 < or = 30; 237 were 31-55; 91 > 56 years). The majority (329 patients, 86.1%) were male and the most common indications for OHT were ischemic (n = 180) and idiopathic (n = 171) cardiomyopathy. Total ischemic time (TIT) was 202.4 +/- 84.5 minutes (range 47-457 minutes). In 86 donors TIT was under 2 hours while it was between 2 and 4 hours in 168, and more than 4 hours in 128 donors. Actuarial survival was 80%, 73%, and 55% at 1, 5, and 10 years respectively. By Cox proportional hazards models, recipient status (Status I-II vs III-IV; risk ratio 1.75; p = 0.003) and donor age, examined as either a continuous or categorical variable ([age < 35 vs > or = 35; risk ratio 1.98; p < 0.001], [age < 50 vs > or = 50; risk ratio 2.20; p < 0.001], [age < 35 vs 35-49 versus > or = 50; risk ratio 1.83; p < 0.001]), were the only predictors of operative mortality. In this analysis, total graft ischemic time had no effect on survival. However, using the Kaplan-Meier method followed by Mantel-Cox logrank analysis, ischemic time did have a significant effect on survival if donor age was > 50 years (p = 0.009). By stepwise logistic regression analysis, a probability model for survival was then developed based on donor age, the interaction between donor age and ischemic time, and patient status. CONCLUSIONS: Improvements in myocardial preservation and peri-operative management may allow for the safe utilization of donor organs with prolonged ischemic times. Older donors are associated with decreased peri-operative and long-term survival following. OHT, particularly if graft ischemic time exceeds 240 minutes and if these donor hearts are transplanted into urgent (Status III-IV) recipients.

The effect of prosthetic valve type on survival after aortic valve surgery.

A number of recent reports have suggested that valve design has an influence on long-term survival after aortic valve replacement (AVR). The present study examines the clinical results of two large multicenter trials of the Hancock II stented and Medtronic Freestyle stentless bioprosthetic valves. In all cases a subcoronary implant technique was used. All patients were operated on between 1991 and 1994, and all patients were monitored for 5 years. The 5-year actuarial survival rate was 86% for Freestyle and 77% for Hancock patients (P<.05). Late mortality occurred in 40 Freestyle patients (8.8%) compared with 36 Hancock II patients (16.1%, P = .0074). Cox's proportional hazard models were used to identify independent predictors of 5-year survival for the two groups. Hazard ratio (HR) and P value are presented in parentheses. The final analysis included the interactive variable valve*age. The resultant model indicates that the interaction of age and valve type has a significant effect on outcome. In patients < or =60 years of age at the time of operation, AVR with a Hancock II valves was associated with nearly a fivefold risk of death compared with patients of the same age who received a Freestyle valve (HR = 4.97, P = .0004). However, this survival advantage decreased by 50% with each decade thereafter (valve*age interaction HR = 0.50, P = .0027). Our data indicate that AVR with a stentless valve confers a survival advantage to the patient. The probability of dying within 5 years of surgery is 50% greater in patients who received a Hancock II versus a Freestyle valve (HR = 1.50, P = .0442). However, this survival advantage is most prominent in younger patients (<60 years of age) where the probability of death is fivefold greater with Hancock than Freestyle valves. With advancing age the benefits of stentless valves are diminished.

Factors affecting left ventricular mass regression after aortic valve replacement with stentless valves.

The hemodynamic benefits of using stentless valves for replacement of the human aortic valve have become more well known. These devices are associated with significant decrease in left ventricular (LV) mass and LV remodeling in the early postoperative period. However, no large study has examined patient-related and valve-related factors that may contribute to this phenomenon. This study examined 1,103 patients who underwent aortic valve replacement (AVR) with a stentless porcine valve (Freestyle = 840, SPV = 263). In all cases, a subcoronary implant technique was used. Valve performance was assessed by serial echocardiograms. At 3 years' post-AVR, mean gradient was 6.3+/-5.0 mm Hg, and effective orifice area (EOA) was 2.0+/-0.7 cm2. Indexed EOA was 1.2+/-0.4 cm2/m2. There was an association between indexed EOA and the extent of LV mass regression. At 3 years after surgery, LV mass index (LVMI) was reduced to 76.3% to 78.7% of baseline in patients whose indexed EOA was >0.8 cm2/m2. In contrast, for patients with an indexed EOA that was <0.8 cm2/m2, LVMI at 3 years was 95.5% of baseline (P = .0001). Multiple linear regression models were used to identify parameters that predicted the 3-year LVMI. Baseline LVMI (P<.0001), prior myocardial infarction (P = .0009), male gender (P = .0036), and carotid stenosis (P = .022) were independent predictors of LV mass regression. Valve type, valve size, preoperative New York Heart Association class symptoms, coronary disease, prior bypass surgery, chronic obstructive pulmonary disease, or underlying valve pathology had no effect on LV mass regression. Data indicate that baseline LVMI and patient-prosthetic mismatch have major effects on the extent of LV mass regression post-AVR. Long-term hemodynamic benefits of AVR can be optimized by proper selection of the prosthesis so as to avoid mismatch. Furthermore, because the baseline LVMI affects the extent of regression post-AVR, early intervention may result in more complete resolution of LV mass postoperatively, which may have important prognostic implications.

Safety and cost-effectiveness of MIDCABG in high-risk CABG patients.

BACKGROUND: Myocardial revascularization without cardiopulmonary bypass has been proposed as a potential therapeutic alternative in high-risk patients undergoing coronary artery bypass grafting. To evaluate this possibility we compared 15 high-risk (HR) patients in whom minimally invasive direct coronary artery bypass grafting was used as the method of revascularization with 41 consecutive patients who underwent conventional coronary artery bypass grafting during 1 month. METHODS: Patients undergoing myocardial revascularization without cardiopulmonary bypass were significantly older than their low-risk (LR) counterparts (72.2 +/- 11.6 versus 63.3 +/- 9.7 years, p = 0.006). The demographic profile for HR versus LR patients was as follows: female patients, 60.0% versus 26.8%, p = 0.02; diabetes, 20.0% versus 24.4%, p = 0.7; prior stroke, 33.3% versus 7.4%, p = 0.03; chronic obstructive pulmonary disease, 60.0% versus 9.8%, p < 0.0001; peripheral vascular disease, 33.3% versus 12.2%, p = 0.03, congestive heart failure, 26.6% versus 9.8%, p = 0.09; impaired left ventricular (ejection fraction < 0.40), 40.0% versus 17.0%, p = 0.07; urgent operation, 86.6% versus 46.3%, p < 0.0001; and redo operation, 20.0% versus 0%, p = 0.003. RESULTS: There were no deaths in the HR group and one death in the LR group. The average intensive care unit stay was 1.1 +/- 0.5 days in HR patients versus 1.6 +/- 1.6 days in LR individuals (p = 0.2), and the average hospital stay was 6.1 +/- 1.8 versus 7.3 +/- 4.4 days, respectively (p = 0.3). We used an acuity risk score index developed by the Adult Cardiac Care Network of Ontario to predict outcome in the HR group. The expected intensive care unit stay in HR patients was 4.1 +/- 1.2 days (versus the observed stay of 1.1 +/- 0.5 days, p < 0.0001), and the expected hospital stay was 12.5 +/- 1.5 days (versus the observed stay of 6.1 +/- 1.8 days, p < 0.0001). The expected mortality in the HR group was 6.1% versus 0%, p = 0.3. A cost regression model was used to examine predicted versus actual cost (in Canadian dollars) for the HR patient cohort (based on Ontario Ministry of Health funding). The expected cost for the HR cohort would have been $11,997 per patient. In contrast, the average cost for these 15 patients was $5,997 per patient, an estimated cost saving of 50%. CONCLUSIONS: Myocardial revascularization without cardiopulmonary bypass appears to be a safe and cost-effective therapeutic modality for HR patients requiring myocardial revascularization.

Coronary bypass with arterial conduits.

To assess the efficacy of arterial revascularization 368 patients were studied who underwent myocardial revascularization with two or more arterial conduits (group M) and compared with 2092 patients in whom a single internal mammary artery +/- veins (group S), and to a third group in which only saphenous vein conduits (group V, n = 602) were used. Group M patients were younger (aged 54.0(9.5) years; 4.1% aged > 70 years) than either group V (67.6(8.9) years, 40.7% > 70 years, P < 0.0001) or group S patients (62.0(8.5) years, 15.7% > 70 years, P < 0.0001). Furthermore, this cohort group had the lowest percentage of females (8.4%), of urgent cases (21.7%), of preoperative myocardial infarction (6.0%), and of redo surgery (0.8%). In contrast, patients who received only saphenous vein conduits had the highest proportion of female patients (29.2%), of urgent cases (47.4%), of preoperative myocardial infarction (16.5%), and of redo surgery (5.5%). By multivariate logistic regression analysis (odds ratio in parentheses), redo surgery (6.06, P = 0.0001), preoperative intra-aortic balloon pump assist (6.11, P = 0.0001), diabetes (1.97, P = 0.03), urgent surgery (1.80, P = 0.05), and advanced age (2.14, P = 0.01) were all predictors of operative mortality. In contrast, while choice of conduit appeared to influence outcome by univariate analysis (4.2% mortality in group V, P < 0.001), it was not found to be a predictor of either mortality or morbidity by regression analysis. The present results indicate that, in carefully selected patients, despite increased technical demands with longer periods of aortic occlusion and longer pump times, multi-arterial grafting (compared with conventional revascularization) is a safe and efficacious procedure. Whether or not this approach to revascularization will increase long-term survival and freedom from reoperation will require further study.

Clinical and hemodynamic comparison of the Medtronic Freestyle and Toronto SPV stentless valves.

The excellent hemodynamics of stentless valves have been observed by numerous investigators. With the recent release of the Toronto SPV (stentless porcine valve) and the Medtronic Freestyle stentless valves in North America, it is appropriate to now compare the clinical and hemodynamic performance of these devices. We analyzed the results of 995 patients who underwent aortic valve replacement (AVR) with either of the two valves; in all cases a subcoronary implant technique was used. There were important differences in the preoperative characteristics for the two groups: Medtronic Freestyle patients were notably older than the Toronto SPV patients (70.7+/-8.6 vs 61.8+/-11.1 years, p < 0.001) and were markedly more symptomatic (p < 0.0001). In the Toronto SPV group, most patients had New York Heart Association (NYHA) Class II (41.5%) or Class III (44.7%) symptoms preoperatively, while in the Freestyle group, 61.5% were in Class III and 12.5% were in Class IV. There were no notable differences in mortality or morbidity for the two groups. Both devices demonstrated a meaningful decrease in mean gradient and a corresponding increase in effective orifice area (EOA). Furthermore, the indexed EOA (EOA/body surface area [BSA]) was > 1cm2/m2 for all valves indicating there was no patient-prosthetic mismatch. There was a meaningful decrease in left ventricular (LV) mass as well as LV mass index (LVMI) for both devices up to 3 years postoperatively. Our data indicate that there were no differences in clinical outcome or hemodynamic performance of these two valves. Both devices offer excellent results with normalization of LV function.

Hemodynamic benefits of the Toronto Stentless Valve.

We report on 254 consecutive patients (170 male, 84 female) undergoing aortic valve replacement with the Toronto SPV Stentless Valve (St. Jude Medical, Inc., St. Paul, Minn.). Mean age (+/- standard deviation) was 62.1 +/- 11.6 years. Three patients (1%) received sizes 21 or 22 mm, 24 (9%) received size 23 mm, and 227 patients (89%) received sizes 25, 27, or 29 mm. Serial echocardiography was used to assess valve performance during a 3-year follow-up. Mean gradient decreased by 35.8% (p < 0.0001; 95% confidence interval -39.6%, -31.7%) from postoperative values to the 3- to 6-month follow-up and by 6.1% (p = 0.004; 95% confidence interval -10.1%, -2%) at each subsequent interval; effective orifice area increased by 17.2% (p = 0.0001; 95% confidence interval 12.0%, 22.6%) initially and by 4.4% (p < 0.001; 95% confidence interval 1.8%, 7.0%) thereafter. At 2 years of follow-up, mean gradient was 3.3 +/- 2.1 mm Hg and mean effective orifice area was 2.2 +/- 0.8 cm2. Studies on left ventricular mass were carried out on 84 patients. Left ventricular mass decreased by 14.3% (37.8 +/- 57.9 gm; p < 0.0001; 95% confidence interval -53.7, -21.9 gm) and left ventricular mass index decreased by 15.2% (21.1 +/- 30.5 gm/m2; p < 0.0001; 95% confidence interval -29.5, -12.7 gm/m2) from postoperative values to the 3- to 6-month follow-up interval. The reduction in residual gradient and potential regression in left ventricular hypertrophy may have a beneficial prognostic implication. We believe that the unique stentless design of the Toronto SPV Stentless Valve allows this to occur.

Cardiac pacing following surgery for acquired heart disease.

BACKGROUND: This study is comprised of 3493 consecutive patients who underwent open heart surgery at our institution. Data on all patients were collected prospectively. METHODS: In 45 patients (Group P) (1.3%), a permanent pacemaker (PP) was inserted postoperatively. For the purpose of the study, these patients were compared to 3448 patients (Group NP) who did not require insertion of a PP after surgery. Mean follow-up was 33 months (range 1.5 to 66). RESULTS: We found Group P patients were older (64.8 +/- 11.0 vs 61.0 +/- 11.0 years, p < 0.05), had a higher proportion of elderly (> 70 years) 36% vs 19%, p = 0.01), and of female patients (48.8% vs 22.7%, p < 0.001) compared to Group NP. Group P also had a higher incidence of preoperative rhythm abnormalities (26.6% vs 5.7%, p < 0.0001), redo surgery (13.3% vs 4.6%, p = 0.02), aortic valve surgery (48.8% vs 10.8%, p < 0.001), and tricuspid valve surgery (repair 3, replacement 1) (8.8% vs 0.5%, p < 0.001), in addition to a higher proportion of patients in whom cold (vs warm) blood cardioplegia was used (68.8% vs 52.3%, p = 0.03). Indication for postoperative PP was sick sinus syndrome (SSS) in nine patients; atrial fibrillation in eight patients; atrioventricular block (AVB) in 27 patients; and combined AVB/SSS in 1 patient. There were no operative deaths in Group P. Necessity for PP after heart surgery had a significant impact on resource utilization resulting in prolonged ventilation (3.1 +/- 7.5 vs 1.4 +/- 3.3 days, p < 0.01), intensive care unit (5.1 +/- 10.2 vs 2.5 +/- 4.0 days, p < 0.01), and postoperative hospital stay (18.0 +/- 13.4 vs 8.1 +/- 9.4 days, p < 0.01). CONCLUSIONS: By multivariate logistic regression (odds ratio and p value in parentheses), aortic valve surgery (8.23, p = 0.001), the absence of preoperative sinus rhythm (5.60, p = 0.001), postoperative myocardial infarction (3.46, p = 0.024), and female gender (2.52, p = 0.003), were found to be independent predictors for PP requirement post surgery.

The current status of myocardial revascularization: changing trends and risk factor analysis.

From November 1989 to December 1994, we performed 2264 bypass procedures. Data were collected prospectively. The population was divided into three subgroups: group 1 = single internal mammary artery (IMA) +/- veins (n = 1584); group 2 = veins only (n = 503); and group 3 = two or more arterial conduits +/- veins (n = 177). Patients who received only saphenous vein conduits (group 2) were significantly older (66.7 +/- 8.9 years) than either group 1 (60.3 +/- 8.3 years) or group 3 (51.6 +/- 9.2 years). Furthermore, this cohort group had the highest percentage of females (28.6%), urgent cases (43.5%), preoperative myocardial infarction (MI) (18.5%), and redo surgery (5.4%). In contrast, patients who received two or more arterial conduits were 94.9% male, and had the lowest incidence of urgent cases (18.1%) and redo surgery (0.5%). Mortality was 1.4% in group 1 and 3.2% in group 2; there were no deaths in group 3. Furthermore, group 2 patients had the highest incidence of perioperative MI (6.6%), low output syndrome (22.1%), intra-aortic balloon pump (IABP) assist (6.2%), and stroke (2.7%). By multivariate logistic regression analysis (odds ratio in parentheses), redo surgery (7.92), preoperative IABP (5.53), poor LV function (4.01), renal impairment (3.94), and advanced age (2.12) were all predictors of operative mortality. When mortality and morbidity (death, infarction, low output syndrome, IABP assist) were combined, regression analysis revealed that in addition to the above variables, female gender and cold cardioplegia were also independent predictors of combined mortality and morbidity. Resource utilization was determined for the three patient groups. There was concern that the increased technical demands of multiple arterial grafting along with longer periods of aortic occlusion and pump times may lead to increased complications and prolonged hospital stay. However, we found that group 3 had the lowest ventilation time, intensive care unit stay, and hospital stay. The results no doubt were influenced by case selection. Whether or not this approach to revascularization will increase long-term survival and freedom from reoperation will require further study.

Autologous pericardial patch without infarctectomy for the treatment of acute cardiac rupture.

Acute cardiac rupture is a complication of acute myocardial infarction and is often a lethal condition. The successful management of a case of left ventricular rupture by patch repair with concomitant myocardial revascularization is reported. Pre- and postoperative hemodynamic stabilization was achieved with the aid of intra-aortic balloon pump counterpulsation.

The technique of radial artery bypass grafting and early clinical results.

There is renewed interest in the use of the radial artery as a conduit for coronary artery bypass. Fifty patients underwent bypass surgery using the radial artery in addition to other conduits between November 24, 1992 and November 8, 1994 at our institution. The mean age was 54.4 +/- 9.1 years (mean +/- SD) and 47 of the patients were male. There were 3.6 +/- 0.9 and stomses per patient, of which 2.2 +/- 0.4 were arterial anastomoses. The most common target vessel for the radial artery has been the obtuse marginal (58.8%), with the aorta as the usual site for proximal anastomosis (80.4%). There have been no ischemic hand complications and no radial nerve deficits. There have been no early or late deaths and no myocardial ischemic complications related to the use of the radial artery. We present the techniques used at our institution for the use of the radial artery as a conduit for coronary artery bypass.

Aortic valve replacement with a stentless porcine bioprosthesis: multicentre trial. Canadian Investigators of the Toronto SPV Valve Trial.

OBJECTIVE: To evaluate the clinical and hemodynamic performance of a new bioprosthesis for replacement of the aortic valve in humans. STUDY DESIGN: In a multicentre clinical trial between July 1991 and January 1994, 118 patients underwent aortic valve replacement with the Toronto SPV valve. RESULTS: Valvular pathology was aortic stenosis in 58%, insufficiency in 12% and mixed valvular disease in 30%; congenital bicuspid aortic valve was seen in 42% while heavy calcification was present in 86%. In approximately a third of the patients, concomitant coronary artery bypass surgery was performed. The mean period of aortic occlusion was 89 mins (range 48 to 180). Valve sizes implanted were: 22 mm (1%), 23 mm (7.6%), 25 mm (22.9%), 27 mm (37.3%) or 29 mm (31.4%). There were three deaths in the series: two from subacute bacterial endocarditis and one suicide. Early complications were cardiac arrest (0.8%), thromboembolism (2.5%) and arrhythmia (12.7%), while late complications were cardiac arrest (0.8%), arrhythmia (4.7%), angina (0.8%), thromboembolism (4.4%), endocarditis (1.7%) and other sepsis (0.8%). There were no valve related failures in 119 valve-years (mean follow-up 1.01 valve-year per patient). Follow-up echocardiography demonstrated an average decrease in mean systolic gradient of 36% from early to late postoperative period (P < 0.001) and an average increase in effective orifice area of 35% (P < 0.001) in the same period. No regurgitation was noted in 91% of patients at early, and 89% of patients at late, follow-up. CONCLUSIONS: The Toronto SPV valve offers excellent hemodynamics, is relatively easy to insert and has few valve related complications. The observed changes in transvalvular area over time are consistent with a hypothesis that the ventricle undergoes remodelling following aortic valve replacement with this bioprosthesis. Longer follow-up is required to determine durability.

Stentless porcine bioprosthesis for aortic valve replacement.

We report herein our experience with the Toronto Stentless Porcine Valve (Toronto SPV, manufactured by St. Jude Medical Inc., Minneapolis, MN, USA) for aortic valve replacement (AVR). To date 146 SPV valves have been implanted, 29 in an initial clinical trial (from October 1987 to April 1987) and 117 in the current FDA trial (September 1991 to January 1994). In the current trial the majority of patients were male (76%), aortic stenosis was the dominant lesion (73%) and 68% of the patients received a valve size 27 mm or greater. The mean age was 61.3 +/- 12.0 years. For the entire group there has been no hospital death and no patient has required a pacemaker. Perioperative complications were myocardial infarction in three patients and suspect subacute bacterial endocarditis (medically treated) in three patients. There have been two late deaths (2%), two patients have had transient ischemic attacks (2%), and one patient suffered stroke with complete neurological recovery (1%). To date there has been no case of primary valve failure. Echocardiographic assessment of the SPV valve has demonstrated excellent effective valve orifice areas with very low transvalvular gradients and 95% of the patients had either 0 or 1+ insufficiency. These results are encouraging and justify the continued use of this valve in clinical trials. Further follow-up is required to determine its durability.

Initial clinical experience with the Toronto Stentless Porcine Valve.

We report our initial experience from April 1992 to November 1993 with a stentless porcine valve (Toronto SPV Valve, St. Jude Medical) for aortic valve replacement (AVR) in 21 consecutive patients and compare this group to a matched cohort that underwent AVR with a Hancock II (Medtronic) bioprosthesis. There were no hospital deaths in either group. Postoperative hospitalization was 5.5 +/- 0.8 versus 7.0 +/- 2.3 days (p = 0.004). Aortic cross-clamp time was 114.5 +/- 15.7 min in the SPV group and 96.0 +/- 25.0 min in the Hancock II group (p = 0.003). Complications in the SPV group were: one patient suffered perioperative infarction, one patient required late reoperation for left main stenosis, and one patient died suddenly following femoral thrombectomy at another center. Complications in the Hancock II group included: one patient with postoperative low output syndrome, and two late deaths (one from an aortic dissection and the other from chronic liver disease secondary to alcohol abuse). Comparison data indicate that the average size valve implanted in the SPV group was higher than in the Hancock II group (26.3 +/- 1.9 vs 24.0 +/- 1.9, p = 0.001). In the SPV group, 16 patients had 0 or trivial regurgitation and 1+ regurgitation was seen in 5 patients; regurgitation did not change over a 12-month follow-up. We observed a decrease in gradients over time (p < 0.01). Our results are compatible with a hypothesis that the ventricle undergoes remodeling over time, once the obstruction is relieved. We think the stentless design is an important feature that allows this to occur.(ABSTRACT TRUNCATED AT 250 WORDS)