Low prevalence of heparin-induced thrombocytopenia after cardiac surgery in Thai patients.

INTRODUCTION: Heparin induced-thrombocytopenia (HIT) has been well recognized in Western countries. However, there are no data in the Thai population. We therefore investigated the prevalence of anti-platelet factor 4 (PF4)/heparin antibodies, HIT, and its thrombotic complications in Thai patients undergoing cardiac surgery using unfractionated heparin. MATERIALS AND METHODS: Seventy-three consecutive patients were prospectively enrolled in this study. Blood samples before operation and week 1, week 2, and week 3 after operation were collected from each patient for HIT antibody screening by enzyme-linked immunosorbent assay using IgG antibody specific to the PF4/heparin complex. Positive samples were further analyzed by (14)C-serotonin release assay. Complete blood count was performed daily during the first week, then weekly for 3 weeks. RESULTS: No patient had detectable anti-PF4/heparin antibodies at baseline. Five patients sero-converted during the course of the study for anti-PF4/heparin IgG: 3 (4.1%) at week 1, 4 (5.5%) at week 2, and 5 (6.8%) at week 3 after surgery. However, none of these patients had anti-PF4/heparin antibodies that resulted in (14)C-serotonin release to be considered clinically significant antibodies. Post-operative thrombocytopenia after the operation was found in 35 patients (47.9%), but was not considered to be caused by HIT. Thromboembolic events occurred in 3 patients (4.1%) during follow up; however, none of these patients had positive PF4/heparin antibody tests. CONCLUSIONS: Our study represents the first study to examine Thai patients exposed to heparin in the context of cardiac surgery. We found a lower prevalence of positive anti-PF4/heparin antibodies and clinical HIT than previously published studies.

Predictors of sinus rhythm after radiofrequency maze and mitral valve surgery.

The prevalence and predictors of postoperative sinus rhythm in patients undergoing a radiofrequency ablation maze operation and mitral valve surgery were assessed in 63 patients of whom 54 (86%) were in permanent atrial fibrillation. Operative mortality was 3.17%. At a median follow-up of 18 months, 54 (88.5%) patients were in sinus rhythm and 7 (11.5%) were in atrial fibrillation. The probability of sinus rhythm at 30 months was 92%. Left atrial diameter was the most significant prognostic factor for sinus rhythm on multivariate proportional-hazard regression analysis. The cutoff value of preoperative left atrial diameter for predicting persistent atrial fibrillation at 6 months was 6 cm (100% sensitivity and 73.6% specificity). The radiofrequency ablation maze operation can be performed in addition to mitral surgery with a high rate of successful conversion to sinus rhythm. Preoperative left atrial diameter < 6 cm is an important prognostic factor for sinus rhythm conversion.

Techniques and results of off-pump coronary artery bypass grafting using homemade intracoronary shunt.

BACKGROUND: The outcome of the off-pump coronary artery bypass grafting (CABG) is highly dependent on surgical techniques. To overcome problems of intraoperative hemodynamic instability and avoid potential injury to coronary artery arising from occlusive technique, the authors have modified the strategy of performing distal anastomosis by using the authors' homemade intracoronary artery shunt. OBJECTIVE: To document the results of off-pump CABG using the authors' homemade intracoronary shunt. The characteristics of shunt and techniques are demonstrated. MATERIAL AND METHOD: The shunt is constructed from silicone tubing (Allied Biomedical Company, Paso Robles, CA). It has been successfully used for distal anastomoses in off-pump coronary artery bypass surgery. All 170 consecutive patients who had off-pump CABG from October 2002 to May 2005 were evaluated. Data were collected retrospectively. Average grafts per patient were 3.5. Arterial grafts were used in most cases (90%). Conversion rate was 2.8%. Patients were followed up at 3 weeks, 6 weeks, and bimonthly thereafter. RESULTS: In a 23-month follow-up, the operative mortality rate was 0.5% (one patient). Complications included stroke in 3 patients (1.8%) and post-operative AF in 12 patients (7.12%). Of 170 patients, 12 patients (7.05%) required intraoperative or postoperative intraaortic balloon pump support. The early results were good and satisfactory. CONCLUSION: Off-pump CABG can be successfully performed using the authors' homemade intracoronary artery shunt with better hemodynamic control. The techniques are safe, simple, reliable, and effective.