Cheol Hyun Chung

Comparison of radial artery patency according to proximal anastomosis site: Direct aorta to radial artery anastomosis is superior to radial artery composite grafting

OBJECTIVEnThe radial artery is frequently the second graft of choice after the left internal thoracic artery in coronary artery bypass graft surgery. However, the optimal radial artery proximal anastomosis site remains controversial. The aim of the present study was to compare the radial artery patency according to its use as either an aorta-radial artery graft or composite radial artery graft in coronary artery bypass grafting.nnnMETHODSnA total of 1735 patients received coronary artery bypass grafting using the radial artery between January 2001 and July 2007, of whom 893 received serial computed tomographic coronary angiographies; these patients formed the basis of the current study. The patients were divided into 2 groups: group I (direct radial artery to aortic anastomosis, n = 451 patients) and group II (radial artery composite grafting with the left internal thoracic artery, n = 442 patients). The number of distal radial artery anastomoses performed in group I was 657 and 749 in group II. Sequential bypassing was performed in 399 patients.nnnRESULTSnThe early patency rate was significantly higher in group I than in group II (98.3% vs 94.5%; P = .004). The 1-, 2-, and 5-year patency rates were also higher in group I than in group II (93.8% +/- 1.2%, 90.5% +/- 1.6%, and 74.3% +/- 6.1%, vs 90.5% +/- 1.4%, 85.3% +/- 1.9%, and 65.2% +/- 4.2%, respectively; P = .004). Multivariate analysis showed composite grafting (P = .02), the degree of target vessel stenosis <90% (P = .001), and the target revascularization site (P = .005) to be significant risk factors for occlusion.nnnCONCLUSIONnThe results of the current data showed superior early and late patency rates of coronary artery bypass grafting with radial artery to aorta anastomosis compared with left internal thoracic artery-radial artery composite grafting.

Impact of the Maze operation on the progression of mild functional tricuspid regurgitation

OBJECTIVESnIn patients having mitral valve surgery, concomitant surgery for mild functional tricuspid regurgitation remains the subject of debate. This study examined the effect of Maze operation and tricuspid valve repair on postoperative functional tricuspid regurgitation progression.nnnMETHODSnThe study retrospectively analyzed 250 patients (86 men, 164 women) with mild functional tricuspid regurgitation (grade 2) who had mitral valve surgery between January 1994 and July 2006. Based on follow-up data, patients were defined as either stable (n = 209, 83.6%) or aggravated (n = 41, 16.4%). Predictors for significant tricuspid regurgitation development were identified using Cox regression analysis.nnnRESULTSnThe mean follow-up time was 62.6 +/- 39.8 months after surgery. Although most mitral valve procedures were successful, there was an increase in the incidence of significant functional tricuspid regurgitation overall from immediately postoperative to final assessment (5.2% to 16.4%, P < 0.01). Univariate analysis showed that old age, shorter aortic crossclamping time, and omission of Maze operation were associated with functional tricuspid regurgitation progression. Multivariate analysis showed that older age (adjusted hazard ratio, 1.05; 95% confidence interval, 1.02 to 1.08), a rheumatic etiology of the mitral valve disease (adjusted hazard ratio, 2.31; 95% confidence interval, 1.21 to 4.42), and no Maze operation (adjusted hazard ratio, 7.90; 95% confidence interval, 1.90 to 32.86) were independent predictors of mild functional tricuspid regurgitation progression. For the 168 patients with preoperative atrial fibrillation, Maze operation improved the tricuspid regurgitation-free survival significantly (P < .01) but tricuspid valve repair showed no significant difference.nnnCONCLUSIONSnMild functional tricuspid regurgitation can progress postoperatively despite successful mitral valve surgery. Although tricuspid valve repairs alleviate progression of functional tricuspid regurgitation, concomitant Maze operation is a more powerful protective factor against mild functional tricuspid regurgitation progression.

Long-term mortality in adult orthotopic heart transplant recipients.

Heart transplantation is now regarded as the treatment of choice for end-stage heart failure. To improve long-term results of the heart transplantation, we analyzed causes of death relative to time after transplantation. A total of 201 consecutive patients, 154 (76.6%) males, aged ≥ 17 yr underwent heart transplantation between November 1992 and December 2008. Mean ages of recipients and donors were 42.8 ± 12.4 and 29.8 ± 9.6 yr, respectively. The bicaval anastomosis technique was used since 1999. Mean follow up duration was 6.5 ± 4.4 yr. Two patients (1%) died in-hospital due to sepsis caused by infection. Late death occurred in 39 patients (19.4%) with the most common cause being sepsis due to infection. The 1-, 5-, and 10-yr survival rates in these patients were 95.5% ± 1.5%, 86.9% ± 2.6%, and 73.5% ± 4.1%, respectively. The surgical results of heart transplantation in adults were excellent, with late mortality due primarily to infection, malignancy, and rejection. Cardiac deaths related to cardiac allograft vasculopathy were very rare.

Mitral-aortic intervalvular fibrosa pseudoaneurysm resulting in the displacement of the left main coronary artery after aortic valve replacement.

control chest CT scan was taken on the second postoperative day (Figure 2). It was recognized that the bullet had migrated to the left posteroinferior pulmonary artery. Nevertheless, throughout the patient’s hospital stay, no signs of pulmonary embolism or infection could be observed. Pulmonary and laboratory test results were almost normal (aspartate aminotransferase, 33 IU/L; alanine aminotransferase, 20 IU/L; lactate dehydrogenase, 247 IU/L) on the second day. He was discharged 8 days after the emergency operation.

Risk factors analysis on failure of maze procedure: mid-term results.

OBJECTIVEnSince the late 1980s, surgical ablation of atrial fibrillation (AF) has been one of the most effective means of curing this arrhythmia. However, about 20% of patients who underwent maze procedures have shown recurrence of AF during the follow-up periods. The aim of this study is to evaluate our result of maze procedures in last decade and to analyze the risk factors of maze failure.nnnMETHODSnBetween July 1997 and July 2007, 560 consecutive patients underwent maze procedures for AF by a single surgeon. Demographics showed that average age of the patients is 51.3 years, with a slight female predominance (M:F = 248:312). Most of the maze procedures had been performed in conjunction with mitral valve (n = 494, 88.6%), while only six cases (1.1%) were performed with isolated maze procedure. The maze failure was defined as showing any rhythm besides normal sinus rhythm at the last follow-up. Univariate and multivariate analysis for the risk factors of maze failure were identified. The survival impact of maze failure was also evaluated.nnnRESULTSnThe in-hospital mortality (1.6%) was acceptable. During the 29.7 months of median follow-up period, the late mortality rate was 3.8% and permanent pacemaker insertion was necessary in 2.3% (n = 13) of the patients. The success rate of maze was 84.1% (471/560) and effective left atrial contraction was identified in 97.2% (458/471) of these patients. In multivariate analysis, the size of left atrium larger than 60 mm, cardiothoracic ratio over 60%, fine AF wave in preoperative ECG, no early normal sinus restoration and simplified surgical ablation were found as an independent predictor of maze failure. Furthermore, the patients with successful maze showed better long-term survival rates.nnnCONCLUSIONSnThe results of our maze procedure during the last decade showed an acceptable success rate and the patients who were restored to sinus rhythm after maze procedures showed better long-term survival rates. For the patients who have independent biological risk factors, more thorough ablation lesion set is recommended for better long-term results.

The impact of sequential versus single anastomoses on flow characteristics and mid-term patency of saphenous vein grafts in coronary bypass grafting

OBJECTIVEnTo assess the influence of bypass grafting technique on the flow characteristics and mid-term patency of saphenous vein coronary bypass grafts.nnnMETHODSnIn the present study, 309 patients who underwent either sequential (group A, N = 84 grafts) or individual (group B, N = 244 grafts) saphenous vein coronary bypass grafting between February 2002 and September 2007 were investigated. Individual bypassing only was performed in 212 patients, and sequential bypassing only was performed in 78 patients. The remaining 19 patients received both. A total of 436 distal anastomoses were performed with 328 saphenous vein grafts. The intraoperative flow characteristics and the graft patency were assessed with the transit time flow meter and serial multi-detector computed tomography coronary angiograms, respectively.nnnRESULTSnGroup A showed a higher mean flow compared with group B at 49.4 ± 27.4 mL/min versus 37.1 ± 20.1 mL/min, respectively (P = .001). The mean flow increased linearly as the number of anastomoses increased per graft (P < .001). Graft patency at 3 years was 93.3% ± 3.4% in group A and 86.5% ± 3.1% in group B (P = .048). After adjustment for baseline characteristics, group A showed a tendency for superior mid-term patency than group B (hazard ratio 0.362; 95% confidence interval, 0.129-1.017; P = .0538).nnnCONCLUSIONSnSequential bypass grafts were associated with higher mean flows and superior mid-term patency compared with individual grafts. These findings suggest the more favorable results of sequential bypass grafting to be attributed to the enhanced flow hemodynamics.

Surgical results of active infective native mitral valve endocarditis: repair versus replacement

OBJECTIVEnThe current study compared clinical outcomes after mitral valve repair or replacement in patients with active infective endocarditis involving only the native mitral valve.nnnMETHODSnFrom January 1994 to December 2009, 102 patients were identified with active infective native mitral valve endocarditis. Mitral valve repair (MVP) was performed in 41 patients and mitral valve replacement (MVR) in 61 patients. The mean age was 34.4 ± 16.9 years in the MVP group and 43.1 ± 14.9 years in the MVR group (p=0.007). The composite end points of cardiac death and cardiac-related morbidities were compared in these two groups using the inverse-probability-of-treatment-weighted method. The median follow-up time was 4.7 years (range, 0.1-15.8) and follow-up was possible in 100 (98%) patients.nnnRESULTSnThere were three in-hospital deaths (2.9%), all in MVR patients (p=0.272). The mean cardiopulmonary bypass time and aortic cross-clamping time were 111.4 ± 34.7 min and 72.7 ± 23.7 min in the MVP group and 101.1 ± 42.9 min and 62.9 ± 26.9 min in the MVR group (p=0.204, p=0.062). The 1-, 5-, and 10-year survival rates were 97.5%, 97.5%, and 81.1%, respectively, in the MVP group and 90%, 85.8%, and 85.8%, respectively, in the MVR group (p=0.316). Actuarial event-free survival at 1, 5, and 10 years was 92.7%, 89.5%, and 72.2% in the MVP group, and 94.8%, 81.0%, and 77.3% in the MVR group (p=0.787), respectively.nnnCONCLUSIONSnThe present study showed that postoperative long-term survival and event-free survival in patients with active infective endocarditis of the native mitral valve were not statistically significantly different regardless of whether patients underwent MVP or MVR.

Mitral durability after robotic mitral valve repair: Analysis of 200 consecutive mitral regurgitation repairs

OBJECTIVESnThe study objective was to review a single-center experience on robotic mitral valve repair to treat mitral regurgitation, with a specific focus on midterm echocardiographic mitral durability. No data assessing the quality or durability of repaired mitral valves are currently available.nnnMETHODSnA total of 200 patients who underwent robotic mitral regurgitation repair using the da Vinci system (Intuitive Surgical, Inc, Sunnyvale, Calif) between August 2007 and December 2012 were evaluated. Serial echocardiographic results and operative and procedural times were analyzed.nnnRESULTSnMitral regurgitation repairs were successfully performed, and no or mild residual mitral regurgitation developed in 98.0% of patients, with no conversion to sternotomy. No in-hospital deaths occurred. Follow-up was completed in 96.5% of patients with a median of 31.4 months (interquartile range, 12.4-42.3 months). During follow-up, 4 late deaths, 2 strokes, 1 low cardiac output, 1 newly required dialysis, and 1 reoperation for mitral regurgitation occurred. Freedom from major adverse cardiac events at 5 years was 87.7% ± 5.1%. Regular echocardiographic follow-up (>6 months) was achieved in 187 patients (93.5%). At a median of 29.6 months (interquartile range, 14.9-45.8 months), 21 patients (10.5%) demonstrated moderate or greater mitral regurgitation. Freedom from moderate or greater mitral regurgitation at 5 years was 87.0% ± 2.6%. Mean cardiopulmonary bypass and crossclamping times were 182.9 ± 48.4 minutes and 110.9 ± 34.1 minutes, respectively, demonstrating a significant decrease in both times according to the chronologic date of surgery.nnnCONCLUSIONSnRobotic mitral regurgitation repair is technically feasible and efficacious, demonstrating favorable midterm mitral durability and improved procedural times as experience increases.

Revascularization of the left anterior descending artery area using a single left internal thoracic artery: auto-Y composite grafting or sequential bypassing.

OBJECTIVEnTo maximize the use of left internal thoracic artery in coronary artery bypass grafting, we have adopted a strategy to revascularize the left anterior descending artery area using a single skeletonized left internal thoracic artery; auto-Y composite grafting and sequential bypassing. This study evaluated graft patency and clinical outcomes after these procedures.nnnMETHODSnBetween 2003 and 2009, 144 patients (112 men; age, 62.9 ± 8.9 years) underwent coronary artery bypass grafting using a single left internal thoracic artery graft to bypass the left anterior descending artery and a diagonal branch. Of them, 57 patients underwent sequential anastomosis (sequential group), and 87 underwent auto-Y composite anastomosis (auto-Y group). Graft patency was assessed using serial multidetector computed tomography.nnnRESULTSnThere were no early mortalities. During a mean follow-up duration of 66.2 ± 44.5 months, there were 8 deaths, including 2 cardiac deaths, and no cases of reintervention. The 2 groups were at similar risks of death on crude and adjusted analyses (Pxa0=xa0.109 and .216). The 2-year patency rates for the LAD site were 98% in the sequential group and 100% in the auto-Y group (Pxa0=xa0.195). The 2-year patency rates for the diagonal artery site were 100% in the sequential group and 92.9% in the auto-Y group (Pxa0=xa0.038).nnnCONCLUSIONSnRevascularization of the left anterior descending artery area using a single skeletonized left internal thoracic artery resulted in excellent clinical outcomes and graft patency using either auto-Y or sequential grafting. However, there was a higher rate of diagonal branch graft occlusion after auto-Y compared with sequential grafting.

Late improvement in graft patency after coronary artery bypass grafting: Serial assessment with multidetector computed tomography in the early and late postoperative settings

OBJECTIVEnGrafts initially showing poor patency after coronary artery bypass grafting have occasionally shown improvement on serial multidetector computed tomography. This study analyzed possible factors associated with this phenomenon.nnnMETHODSnBetween September 2003 and July 2007, 512 patients underwent multidetector computed tomography within 1 month of isolated coronary artery bypass grafting. Among them, 1720 distal anastomoses were made with 1042 arterial and 302 venous conduits. Of these, 95 grafts (in 73 patients) were faint (n = 67) or nonvisualized (n = 28). Seventy-three of these grafts (in 56 patients) had follow-up multidetector computed tomographic evaluation 1 year after surgery and comprised the study group.nnnRESULTSnImprovement in graft patency (faint to patent or nonvisualization to visualization) occurred in 44 grafts (60.3%). Multivariate analysis revealed proximal target vessel stenosis of at least 90% (relative risk, 3.81; P = .009), larger target coronary size (relative risk, 1.72; P = .002), and radial artery graft use (relative risk, 4.44; P = .003) to be significantly associated with the graft patency restoration. Graft patency restoration was most commonly observed in a group of 28 radial artery grafts that were anastomosed to target vessel with proximal stenosis of at least 90%; of these grafts, 24 (85.7%) showed improved graft patency on follow-up.nnnCONCLUSIONSnA large proportion of radial artery grafts initially showing poor opacification after coronary artery bypass grafting demonstrated patency restoration on serial multidetector computed tomography. Larger target vessel size and target vessel stenosis of at least 90% were significant correlative factors.