Hitoshi Okabayashi

Risk factors for wound infection after off-pump coronary artery bypass grafting: should bilateral internal thoracic arteries be harvested in patients with diabetes?

OBJECTIVE Wound infection is a rare but life-threatening complication after coronary artery bypass grafting. Risk factors for wound infection after off-pump bypass grafting and the validity of using bilateral internal thoracic arteries harvested in a skeletonized fashion remain unclear, especially in patients with diabetes. METHODS The data of 1500 consecutive patients having off-pump bypass grafting were prospectively collected from our database based on EuroSCORE. This cohort represents 95% of all patients undergoing coronary bypass during that period and 77% of patients undergoing off-pump bypass grafting who received bilateral internal thoracic artery grafts. Univariate and multivariate analyses were performed for patients with and without wound infection and in the diabetic subgroup. RESULTS Ninety-eight patients had wound infections: 76, impaired wound healing; 7, superficial sternal wound infection; and 12, deep sternal wound infection. Patients with wound infections had a higher prevalence of female gender, atrial fibrillation, history of congestive heart failure, chronic renal failure, peripheral vascular disease, and diabetes. Patients with a wound infection more frequently had bilateral internal thoracic artery grafting, longer operation time, longer hospital stay, and a higher mortality rate. Blood transfusions were required in 43.9% of patients with wound infections and 28.1% of those without wound infections. On logistic regression analysis, female gender and history of congestive heart failure, chronic renal failure, and diabetes mellitus were independent risk factors for wound infection. In patients with diabetes, female gender, atherosclerosis obliterans, chronic renal failure, and use of bilateral internal thoracic artery grafts were independent risk factors for wound infection. CONCLUSIONS Risk factors for wound infection after off-pump coronary artery bypass grafting are comparable with those previously reported for conventional bypass grafting. In patients with diabetes, the use of bilateral internal thoracic arteries, even when harvested in a skeletonized fashion, is a risk factor. Thus, appropriate precautions should be taken in patients with diabetes.

Diagnostic Value of Cardiac CT in the Evaluation of Bicuspid Aortic Stenosis: Comparison With Echocardiography and Operative Findings

OBJECTIVE This study was conducted to assess the diagnostic value of cardiac CT for the evaluation of patients with bicuspid aortic valve disease. MATERIALS AND METHODS Fifty consecutive patients with aortic stenosis who underwent surgical valve repair between September 2005 and November 2006 were examined by ECG-gated CT and echocardiography. A 64-MDCT scanner was used. The image findings regarding the number of leaflets (bicuspid or tricuspid) were compared against the intraoperative findings and were statistically analyzed by one-way univariate analysis of variance. The aortic valve area (AVA) was also measured by CT and echocardiography, and the measured values were statistically compared by use of the paired Students t test. RESULTS Seventeen patients had a bicuspid aortic valve, and 33 had a tricuspid aortic valve. In 10 of the 50 patients, echocardiography was unable to depict the type of aortic valve because of extensive calcification. The sensitivity, specificity, positive predictive value, and negative predictive value for the detection of a bicuspid aortic valve were 76.5%, 60.6%, 68.4%, and 95.2%, respectively, for echocardiography and 94.1%, 100%, 100%, and 97.1%, respectively, for CT. The CT findings were not significantly different from the intraoperative findings (p = 0.99), but the echocardiographic findings were (p < 0.05). The AVA measurements obtained by CT and echocardiography were 0.940 ± 0.44 cm(2) and 0.659 ± 0.234 cm(2), respectively, showing a significant difference (p < 0.05). CONCLUSION ECG-gated cardiac CT is useful for the accurate morphologic assessment of bicuspid aortic stenosis, especially in patients with severe valve calcification.

Benefits of Off-Pump Coronary Artery Bypass Grafting in High-Risk Patients

Background— The benefits of off-pump coronary artery bypass graft (OPCAB) compared with conventional on-pump coronary artery bypass graft (CCAB) remain controversial. Thus, it is important to investigate which patient subgroups may benefit the most from OPCAB rather than CCAB. Methods and Results— Among the patients undergoing first coronary revascularization enrolled in the CREDO-Kyoto Registry (a registry of first-time percutaneous coronary intervention and coronary artery bypass graft patients in Japan), 2468 patients undergoing coronary artery bypass graft were entered into the study (mean age, 67±9 years). Predicted risk of operative mortality (PROM) of each patient was calculated by logistic EuroSCORE. Patients were divided into tertile based on their PROM. Mortality rates and the incidences of cardiovascular events were compared between CCAB and OPCAB within each PROM tertile using propensity score analysis. A total of 1377 patients received CCAB whereas 1091 received OPCAB. Adjusted 30-day mortality was not significantly different between CCAB and OPCAB patients regardless of their PROM range. However, the odds ratio of 30-day stroke in CCAB compared with OPCAB in the high-risk tertile was 8.30 (95% confidence interval, 2.25–30.7; P<0.01). Regarding long-term outcomes, hazard ratio of stroke in CCAB compared with OPCAB in the high-risk tertile was 1.80 (95% confidence interval, 1.07–3.02; P=0.03). Nevertheless, hazard ratio of overall mortality in the high-risk tertile was 1.44 (95% confidence interval, 0.98–2.11; P=0.06), indicating no statistically significant difference between the 2 procedures. Conclusions— OPCAB as opposed to CCAB is associated with short-term and long-term benefits in stroke prevention in patients at higher risk as estimated by EuroSCORE. No survival benefit of OPCAB was shown regardless of preoperative risk level.

Cardiac papillary fibroelastomas: Rationale for excision

We experienced a case of papillary fibroelastoma of the left ventricular outflow tract in a patient with severe valvular heart disease that was detected only by transesophageal echocardiography. Preoperative detection of this lesion altered the surgical procedure to include resection of the mass through the aortic valve annulus along with repair/replacement of the valves. The literature documents sufficient morbidity/mortality to support excision of these lesions regardless of symptoms or location.

Comparison of Long-Term Outcome After Percutaneous Coronary Intervention Versus Coronary Artery Bypass Grafting in Patients With Unprotected Left Main Coronary Artery Disease (from the CREDO-Kyoto PCI/CABG Registry Cohort-2)

The long-term outcome of percutaneous coronary intervention (PCI) compared to coronary artery bypass grafting (CABG) for unprotected left main coronary artery disease (ULMCAD) remains to be investigated. We identified 1,005 patients with ULMCAD of 15,939 patients with first coronary revascularization enrolled in the CREDO-Kyoto PCI/CABG Registry Cohort-2. Cumulative 3-year incidence of a composite of death/myocardial infarction (MI)/stroke was significantly higher in the PCI group than in the CABG group (22.7% vs 14.8%, p = 0.0006, log-rank test). However, the adjusted outcome was not different between the PCI and CABG groups (hazard ratio [HR] 1.30, 95% confidence interval [CI] 0.79 to 2.15, p = 0.30). Stratified analysis using the SYNTAX score demonstrated that risk for a composite of death/MI/stroke was not different between the 2 treatment groups in patients with low (<23) and intermediate (23 to 33) SYNTAX scores (adjusted HR 1.70, 95% CI 0.77 to 3.76, p = 0.19; adjusted HR 0.86, 95% CI 0.37 to 1.99, p = 0.72, respectively), whereas in patients with a high SYNTAX score (≥33), it was significantly higher after PCI than after CABG (adjusted HR 2.61, 95% CI 1.32 to 5.16, p = 0.006). In conclusion, risk of PCI for serious adverse events seemed to be comparable to that after CABG in patients with ULMCAD with a low or intermediate SYNTAX score, whereas PCI compared with CABG was associated with a higher risk for serious adverse events in patients with a high SYNTAX score.

Comparison of Percutaneous Coronary Intervention With Coronary Artery Bypass Grafting in Unprotected Left Main Coronary Artery Disease – 5-Year Outcome From CREDO-Kyoto PCI/CABG Registry Cohort-2 –

BACKGROUND Studies evaluating long-term (≥5 years) outcome of percutaneous coronary intervention (PCI) compared with coronary artery bypass grafting (CABG) in patients with unprotected left main coronary artery disease (ULMCAD) are still limited, despite concerns for late adverse events after drug-eluting stents implantation. METHODS AND RESULTS We identified 1,004 patients with ULMCAD (PCI: n=364, CABG: n=640) among 15,939 patients with first coronary revascularization enrolled in the CREDO-Kyoto PCI/CABG registry cohort-2. The primary outcome measure in the current analysis was a composite of death, myocardial infarction, and stroke (death/MI/stroke). The cumulative 5-year incidence of and the adjusted risk for death/MI/stroke were significantly higher in the PCI group than in the CABG group (34.5% vs. 24.1%, log-rank P<0.001, adjusted hazard ratio (HR): 1.48 [95% confidence interval (CI): 1.07-2.05, P=0.02]). The adjusted risks for all-cause death was not significantly different between the 2 groups. Regarding the stratified analysis by the SYNTAX score, the adjusted risk for death/MI/stroke was not significantly different between the 2 groups in patients with low (<23) or intermediate (23-33) SYNTAX score, whereas it was significantly higher in the PCI group than in the CABG group in patients with high (≤33) SYNTAX score. CONCLUSIONS CABG as compared with PCI was associated with better long-term outcome in patients with ULMCAD, especially those with high anatomical complexity.

Three-year outcome after percutaneous coronary intervention and coronary artery bypass grafting in patients with triple-vessel coronary artery disease: observations from the CREDO-Kyoto PCI/CABG registry cohort-2.

AIMS We sought to investigate medium-term outcome of percutaneous coronary intervention (PCI) compared with coronary artery bypass grafting (CABG) in patients with triple-vessel coronary artery disease (TVD). METHODS AND RESULTS We identified 2,981 patients with TVD (PCI: N=1,825, CABG: N=1,156) among 15,939 patients with first coronary revascularisation enrolled in the CREDO-Kyoto PCI/CABG registry cohort-2. Excess adjusted three-year risk of the PCI group relative to the CABG group for death/myocardial infarction (MI)/stroke was significant (HR 1.47 [95% CI: 1.13-1.92, p=0.004]). Adjusted risk for all-cause death was also significantly higher with PCI as compared with CABG (HR 1.62 [95% CI: 1.16-2.27, p=0.005]), while risk for cardiac death was neutral between the two groups (HR 1.3 [95% CI: 0.81-2.07, p=0.28]). PCI was also associated with a markedly higher risk for any coronary revascularisation. Regarding the analysis stratified by the SYNTAX score, the adjusted HR of PCI relative to CABG for death/MI/stroke was 1.66 (95% CI: 1.04-2.65, p=0.03) in the low-score (<23: N=874, and N=257), 1.24 (95% CI: 0.83-1.85, p=0.29) in the intermediate-score (23-32: N=638, and N=388), and 1.59 (95% CI: 0.998-2.54, p=0.051) in the high-score (≥ 33: N=280, and N=375) tertiles, respectively. CONCLUSIONS PCI as compared with CABG was associated with significantly higher risk for serious adverse events in TVD patients.

Comparison of Frequency of Postoperative Stroke in Off-Pump Coronary Artery Bypass Grafting Versus On-Pump Coronary Artery Bypass Grafting Versus Percutaneous Coronary Intervention

The stroke rate after coronary artery bypass grafting (CABG) compared to percutaneous coronary intervention (PCI) is generally considered high because cardiopulmonary bypass and aortic manipulations are often associated with cerebrovascular complications. However, an increasing number of CABGs performed without cardiopulmonary bypass (OPCAB) may improve those outcomes. Of 6,323 patients with multivessel and/or left main coronary artery disease, 3,877 patients underwent PCI, 1,381 conventional on-pump CABG, and 1,065 OPCAB. Median follow-up was 3.4 years. Stroke types were classified as early (onset of stroke within 24 hours after revascularization), delayed (within 30 days), and late (after 30 days). Propensity score analysis showed that the incidences of early, delayed, and late stroke did not differ between PCI and OPCAB (0.65, 95% confidence interval 0.08 to 5.45, p = 1.00; 0.36, 0.10 to 1.29, p = 0.23; 0.81, 0.52 to 1.27, p = 0.72, respectively). In contrast, incidence of early stroke after on-pump CABG was higher than after OPCAB (7.22, 1.67 to 31.3, p = 0.01), but incidences of delayed and late stroke were not different (1.66, 0.70 to 3.91, p = 0.50; 1.18, 0.83 to 1.69, p = 0.73). In conclusion, occurrence of stroke was not found to differ in patients after PCI versus OPCAB regardless of onset of stroke. Occurrence of early stroke after OPCAB was lower than that after on-pump CABG, yet occurrences of delayed and late strokes were similar for the 3 revascularization strategies.

Ethnic differences in the VKORC1 gene polymorphism and an association with warfarin dosage requirements in cardiovascular surgery patients.

OBJECTIVES Vitamin K epoxide reductase (VKORC1) is the drug target for inhibition by coumarin-based anticoagulant drugs such as warfarin. Warfarin therapy has been reported as a leading cause of drug-related hospitalization and there is therefore an urgent need to develop tests for better warfarin prescription. We report here the distribution of the intron 1 -136 T>C (1173 T>C intron) polymorphism of VKORC1, previously reported to be associated with warfarin maintenance dose in Caucasians and Japanese, in several ethnic populations from Japan and Israel, and describe its significance for warfarin dosage in Japanese cardiovascular surgery patients. METHODS Subjects consisted of 132 Japanese individuals and 341 Israeli individuals from four Jewish ethnic groups (86 Ashkenazi Jews, 95 Yemenite Jews, 73 Moroccan Jews and 87 Libyan Jews). In addition, 31 Japanese patients receiving warfarin therapy after cardiovascular surgery, maintained with a target International Normalized Ratio, were studied. The genotyping for the 1173 T>C intron polymorphism of VKORC1 was determined using rapid real-time PCR. RESULTS The allele frequency of the combined VKORC1 1173 CT and CC genotypes varied among the four Israeli ethnic groups and was, on average, much higher in the Israeli (0.728) than in the Japanese population (0.152). For the Japanese cardiovascular surgery patients, the maintenance dose of warfarin was significantly larger in the combined VKORC1 1173 TC and CC genotype group than in the 1173 TT genotype group (3.6 +/- 0.5 mg vs 2.8 +/- 0.7 mg, respectively; p = 0.02). CONCLUSION The frequencies of the intron 1 VKORC1 1173 T>C SNP show significant differences between ethnic groups and are associated with warfarin dose requirements for achieving a recommended International Normalized Ratio range in Japanese cardiovascular surgery patients. This study supports the example of warfarin as an appropriate model for applying personalized medicine for anticoagulant drugs, and highlights the importance of ethnicity in pharmacogenetics.

Up to 8-year follow-up of valve replacement with carbomedics valve.

BACKGROUND The aim of this study was to report midterm valve replacement (VR) results with the Carbo-Medics valve (Sulzer Carbomedics, Austin, TX). METHODS From 1991 to 1999, 468 patients aged 13 to 76 years (mean 56 years) underwent VR with CarboMedics valve: 239 aortic (A), 167 mitral (M), and 62 A+M or double valve replacement (DVR). Mean follow-up time was 4.4 years; follow-up was 99.1% complete for 2,016 patient-years (PY). The anticoagulation level was targeted to an international normalized ratio of 1.47 to 2.8. RESULTS The hospital mortality rate was 1.2%. Actuarial analysis for the entire group at 7 years for survival was 87%+/-2.3%. Freedom from valve-related death was 94%+/-1.9%. Freedom from thromboembolic and bleeding events, respectively, were as follows: for AVR, 82%+/-4.9% (2.4%/PY) and 88%+/-2.9% (1.6%/PY); for MVR, 95%+/-2.1% (0.8%/PY) and 91%+/-3.1% (1.3%/PY); and for DVR, 96%+/-3.2% (0.7%/PY) and 85%+/-9.7% (1.0%/PY). Actuarial freedom from reoperation was 98%+/-1.4%. CONCLUSIONS The CarboMedics valve can be implanted with satisfactory early mortality and a low incidence of valve-related events even under low-intensity anticoagulation, as shown in a Japanese population.