Gökhan İpek

Midterm angiographic assessment of coronary artery bypass grafting without cardiopulmonary bypass

BACKGROUND Coronary bypass surgery that provides good long-term graft patency can be performed on the beating heart as a viable alternative to conventional coronary artery bypass grafting (CABG). METHODS From September 1993 to December 1996, 696 patients underwent CABG on the beating heart at the Koşuyolu Heart and Research Hospital in Istanbul. Among them, 70 patients were chosen randomly for angiographic assessment of off-pump coronary artery bypass grafting. RESULTS The interval from operation to angiography varied from 24 to 61 months (mean, 36.1+/-10.9 months). The patency rate of left internal mammary-left anterior descending artery anastomoses was 95.59% (patency achieved in 65 of 68 patients) and of vein grafts was 47.06% (patency achieved in 16 of 34 patients) (p < 0.0001). The patency rates of grafts anastomosed to the left anterior descending artery were significantly higher than the rates of the grafts anastomosed to the other coronary arteries (95.71% versus 45.45%, p < 0.0001). Multivariate analysis showed that graft type (p < 0.0001) and hyperlipidemia (p = 0.023) were significant predictors for graft occlusion. Left ventricular function improved significantly after CABG (p = 0.04). Reintervention (using percutaneous transluminal cardiac angioplasty) and reoperation rates were 0.97% and 1.4%, respectively. CONCLUSIONS Off-pump coronary artery bypass grafting appears to produce midterm and long-term patency rates that are comparable to those of conventional techniques; that is especially true in cases of arterial conduits and of conduits anastomosed to the left anterior descending artery.

The dose-related effects of dexmedetomidine on renal functions and serum neutrophil gelatinase-associated lipocalin values after coronary artery bypass grafting: a randomized, triple-blind, placebo-controlled study.

OBJECTIVES Acute kidney failure after coronary artery bypass grafting (CABG) is a serious complication that increases morbidity and mortality rates. Early detection and prevention of this complication are very important. A novel biomarker named neutrophil gelatinase-associated lipocalin (NGAL) can play an important role in early diagnosis of acute kidney injury. Recent studies on the favourable effects of Dexmedetomidine on cardiac surgery have been published. The aim of this study is to investigate whether there is a dose-dependent positive effect of Dexmedetomidine on neutrophil gelatinase-associated lipocalin levels and renal functions when used after CABG. METHODS Our randomized, triple-blinded, placebo-controlled study was conducted among 295 patients scheduled for CABG surgery between August 2009 and March 2011 in a tertiary cardiac and vascular surgery clinic. A total of 90 consecutive patients who met inclusion criteria were randomized and divided into three groups. The first group received a placebo. The second and the third groups received 4 and 8 µg/cc concentration of the Dexmedetomidine infusion, respectively. Infusion rates were regulated to obtain sedation with a Ramsey sedation score of 2 or 3. Patients were regrouped according to the total Dexmedetomidine dose. Statistical analyses of variables including serum neutrophil gelatinase-associated lipocalin values and conventional renal function tests were made for all six possibilities before the blind was broken. RESULTS Results of conventional renal function tests were not significantly different. However, neutrophil gelatinase-associated lipocalin levels for the first postoperative day for placebo, low-dose and high-dose Dexmedetomidine groups were 176.8 ± 145.9, 97.7 ± 63.4 and 67.3 ± 10.9 ng/ml, respectively. These values were significantly different among the groups (P <0.001). CONCLUSIONS In our study, we found that Dexmedetomidine infusion for sedation after CABG under cardiopulmonary bypass can be useful in the prevention of kidney injury. Conventional renal function tests, including blood urea nitrogen, serum creatinine, urine output and creatinine clearance rate measurements typically may not detect the development of acute kidney dysfunction in the first 48-h postoperative period. Differences were detected in renal function in the early postoperative period and the development of acute kidney injury, as determined by measurements of blood NGAL levels, was significant and dose-dependent.

Five-year experience in aortic root replacement with the flanged composite graft

BACKGROUND Replacement of the aortic root with a composite graft containing a prosthetic mechanic valve is the preferred surgical procedure for tailoring the aortic root. The aim of this study is to determine the 5-year experience with the composite root replacement using our new modification of the Bentall technique. METHODS Between January 1996 and June 2001, 96 patients underwent aortic root replacement using a flanged composite graft. Eighty patients (83.3%) were male, and 16 patients (16.7%) were female with a mean age of 48.7 +/- 14.4 years. Indications for operation were a true or false aneurysm (65.6%), severe calcified aortic valve stenosis (4.2%) or severe aortic insufficiency (2.1%) with dilated ascending aorta, acute dissection (2.1%), or combination of indications (26%). Thirty-one patients (32.3%) received a concomitant cardiac procedure. Mean aortic cross-clamp time was 89.5 +/- 28.6 minutes, and mean cardiopulmonary bypass time was 146.2 +/- 45.6 minutes. Total follow-up was 253.9 patient-years. RESULTS Operative mortality was 8.3% (8 patients). The causes of hospital mortality were severe bleeding (3 patients), low cardiac output syndrome (2), acute respiratory distress syndrome (2) and cerebrovascular event (1). No patient died of flange-related complications. Univariate predictors of early mortality were low cardiac output syndrome (p < 0.001), neurologic complication (p = 0.03), and renal complication (p = 0.03). Multivariate analysis demonstrated only low cardiac output syndrome to be significant (p = 0.001) predictor for early mortality. There were five (5.7%) late deaths. Actuarial survival was 82.65% +/- 4.8% at 5 years (1.95% patient-year). Cox proportional hazards regression analysis demonstrated only low cardiac output syndrome to be significant (p = 0.032) predictor for late mortality. Actuarial freedom from prosthetic- and technique-related mortality was 100% at 5 years. CONCLUSIONS The flanged composite graft offers excellent long-term results, with very low prevalence of prosthetic-related complications. The new created sinuses and the flange are especially helpful to continue physiologic function of the aortic root.

Fifteen-year clinical experience with the Biocor porcine bioprostheses in the mitral position

BACKGROUND Bioprosthetic valve use represents a crucial improvement in surgical treatment of mitral valve disease. The aim of this study is to determine the long-term durability of the Biocor porcine bioprosthetic mitral valve. METHODS Between 1985 and 1989, a total of 158 Biocor porcine bioprosthetic valves were placed in the mitral position, and long-term results of these patients were investigated retrospectively in 1999. RESULTS Thirty-day mortality was 4.4% (7 patients). Total follow-up was 1,499 patient-years. Actuarial survival was 83.66% +/- 3% at 5 years, 77.78% +/- 3.36% at 13 years (1.8% patient-year). Multivariate analysis demonstrated younger age, duration of implantation, congestive heart failure, and functional class to be significant predictors of late mortality. Actuarial freedom from valve-related mortality was 98.58% +/- 1% at 15 years (0.13% patient-year). Actuarial freedom from structural valve deterioration was 95.49% +/- 1.8% at 5 years, 70.2% +/- 4.12% at 10 years, and 64.82% +/- 5.34% at 13 years (2.6% patient-year). Actuarial freedom from structural valve deterioration-related reoperation was 98.43% +/- 1.1% at 5 years, 89.15% +/- 2.85% at 10 years, and 76.82% +/- 7.91% at 14 years. Multivariate analysis showed younger age and duration of implantation to be significant predictors of structural valve deterioration and its related reoperation. CONCLUSIONS By studying a 15-year time period, it is seen that this new generation porcine bioprosthetic valve should be considered an alternative for mechanical valves in selected patients.

Long-term comparison of aortic arch replacement with or without elephant trunk procedure via retrograde cerebral perfusion for aortic arch dissection.

OBJECTIVE The aim of this study is to investigate the effects of the duration of retrograde cerebral perfusion (RCP) in patients with aortic arch dissection. METHODS Between 1993 and December 2000, 56 patients were operated on for aortic arch dissection. Elephant trunk procedure was performed in 28 patients (Group A) and semiarcus replacement in 28 patients (Group B). Type I dissection (P=0.003), chronic ethiology (P=0.006), medial degeneration (P<0.001), and preoperative hemodynamic instability (P=0.004) were observed significantly more in Group A. In both groups RCP was used for cerebral protection. RESULTS Hospital mortality was higher in Group A than Group B (32.1% versus 7.1%; P=0.015). Late mortality was observed only in Group A (10.5%; P=0.049). Actuarial survival was 55.1+/-11.55% in Group A and 91.67+/-5.64% in Group B at 5 yr (P=0.0113), while cumulative survival for all patients was 78.38+/-5.77% at 5 yr. RCP time was longer in Group A (62.7+/-16.8 versus 34.2+/-19.5 min; P<0.001). Forward stepwise logistic regression analysis showed that chronic obstructive pulmonary disease (P=0.014) and renal insufficiency (P=0.004) were significantly predictors for hospital mortality, whereas elephant trunk (P=0.052) and RCP (>60 min) (P=0.175) did not increase early mortality. Only hemodynamic instability was significantly (P=0.006) predictors for late mortality. CONCLUSIONS Preoperative severity of dissection, hemodynamic instability or organ dysfunctions impair early or late outcome. Elephant trunk technique with increased RCP time do not increase early or late mortality. To shorten RCP time (<60-65 min) can improve surgical results.

Does conservative surgical approach improve early and late outcome in patients with acute type A aortic dissection

Abstract Objective: Acute type A aortic dissection (AAAD) represents an emergency in cardiac surgery that requires immediate treatment to prevent death due to its fatal complications. The surgical approach is dependent on the involvement of AAAD. Methods: Sixty-one patients were operated for AAAD at our clinic. 48 (78.7%) were male and 13 (21.3%) were female with a mean age of 51±12.3 yr (range, 21–80 yr). Only the ascending aorta was replaced in 33 (54.1%) patients (Group I) and aortic arch replacement was included in 28 (45.9%) patients (Group II). The aortic valve was preserved in 43 (70.5%) patients (Group A) and replaced in 18 (29.5%) patients (Group B). Results: Early mortality rate was 23% (14/61). Multivariate analysis revealed that previous cardiac operations (P=0.048), renal complications (P=0.024), pump time (P=0.024), and cardiac complications (P=0.017) were significantly factors increasing early mortality. Late mortality rate was 8.5% (4/47) and multivariate analysis revealed that pulmonary complication (P=0.015) was the only statistically significant independent risk factor. Arch replacement or aortic valve replacement was not a predictor for early or late mortality. Cumulative survival was 73.8±5.63% at 1 yr and 68.3±6.46% at 7.5 yr. Cumulative survival was not different between groups (P>0.05). Conclusions: Both radical and conservative surgical approaches in AAAD do not differ in mean of early or late results. Surgery before development of hemodynamic instability and prevention of other system complications improves the outcome of surgical treatment in AAAD.

Combined off-pump coronary artery bypass surgery and abdominal aorta aneurysm repair.

There are controversies regarding treatment protocols of concomittant coronary artery disease and abdominal aorta aneurysm, especially when patients have symptoms of both diseases. In this study, we describe the technique of combined off-pump coronary artery bypass grafting and abdominal aorta aneurysm repair succesfully performed in five patients. Coronary revascularization was first performed in all patients. Then repair of abdominal aorta aneurysm was carried out. Simultaneous surgery is believed to shorten cumulative intensive care unit and hospital stay and decrease total hospital costs. Concomitant coronary artery diseases (CAD) and peripheral arterial diseases are frequently seen.1 Combined surgical interventions for both diseases have been performed since 19802 using cardiopulmonary bypass (CPB), but serious mortalities and morbidities, such as massive hemorrhages, cerebral and pulmonary complications have been reported.3 Recently, off-pump cardiac surgery (OPCAB), which is devoid of these devastating side effects, is being performed safely and successfully.

A Simple Method to Prevent Internal Thoracic Artery Tension

Abstract  Tension on the internal mammary artery is a major risk for anastomosis in patients with severe emphysematous lungs. For this reason, it can be necessary to harvest the internal thoracic artery to its origin, to skeletonize it, or as a last resort to use it as a free graft. Sometimes, these maneuvers cannot be enough to solve the problem. A simple suture technique to hang up the pericardium to the chest wall is described that eliminates herniation of emphysematous lungs across mediastinum and reduces tension on the left internal mammary artery. (J Card Surg 2004;19:264‐266)

Volume Reduction Procedures in Giant Left Atrium

Partial left atrial resection was performed in 8 males and 12 females, aged 19 to 63 years, with giant left atrium and mitral valve disease. Preoperatively, 18 patients had atrial fibrillation, and 2 had normal sinus rhythm. Echocardiography revealed left atrial thrombosis in 3 patients and spontaneous echo contrast in 5. The lateral wall of the left atrium, the region between the pulmonary veins, the roof of the atrium, and the tissue parallel to the mitral annulus were resected. Resection was performed using the cardiac autotransplantation technique in 6 patients. The mitral valve was replaced in 9 patients and reconstructed in 11. Mean aortic crossclamp time was 101 ± 35 minutes and total perfusion time was 135 ± 26 minutes. Mean follow-up was 20.4 ± 1.1 months. There was no operative mortality. One patient (5%) died suddenly in the late postoperative period. Left atrial volume was reduced from 265.3 ± 125 mL to 83 ± 43 mL (p < 0.01). Left atrial diameter decreased from 8.02 ± 1.31 cm to 4.4 ± 1.23 cm (p < 0.01). Sinus rhythm was detected in 13 patients (65%) postoperatively. No left atrial thrombosis or spontaneous echo contrast were found during follow-up. Statistically significant reductions in cardiac size and improvements in functional capacity were observed.

Aorto-Left Ventricular Communication through Extracardiac Tunnel

An asymptomatic 24-year-old man underwent surgical correction of an aorto-left ventricular tunnel. A 1-cm opening was found 1 cm above the commissure of the left and right coronary cusps, which communicated with the left ventricle. It was successfully closed by direct suture.