Yi-Cheng Chuang

A new vascular ring connector in surgery for aortic dissection

OBJECTIVE To improve the surgical results of aortic dissection, we used a novel vascular ring connector for anastomosis. METHODS The vascular ring connector is a titanic ring used as a stent in the vascular graft to achieve a quick, blood-sealed, and sutureless anastomosis. From November 2007 to December 2008, 19 consecutive patients (age range 36-77 years; 16 male and 3 female) with aortic dissection underwent open surgery. All patients received aortic reconstruction with vascular grafts (including 5 cases of arch replacement). The combined procedures were 5 Bentall and 4 coronary artery bypass graft operations. RESULTS There were no significant blood leaks from the anastomotic sites. The time required for each anastomosis was 1 to 2 minutes. All patients were discharged uneventfully and are still doing well after a follow-up period of 1 to 12 months. CONCLUSION The vascular ring connector may improve the early surgical results of aortic dissection by reducing both the time for anastomosis and the risk of bleeding and may be an alternative technique for aortic reconstruction. Its usefulness in the routine treatment of aortic dissection warrants further evaluation.

Cardiopulmonary resuscitation in prone position: a simplified method for outpatients.

Background: The efficacy of cardiopulmonary resuscitation (CPR) is vital for saving lives of victims with sudden cardiac arrest. In 1960, Kuowenhoven and colleagues proposed the method that has become standard for CPR. Despite vast input of resources for public education and training of this procedure, its success rate outside hospitals remains poor to dismal. During CPR, restoration of respiration is as important as circulation. But opening the airway and giving effective mouth‐to‐mouth respiration is difficult for lay people to learn. Furthermore, most bystanders are reluctant to do mouth‐to‐mouth respiration because of the risk of infection. Therefore, the general population needs a more simplified CPR method for outpatients. The practice of CPR in the prone position, first proposed by McNeil in 1989, has not been adopted, despite the fact that it meets the desirable requirements of ideal resuscitation: simultaneous restoration of circulation and respiration with a very simple maneuver. Methods: Part 1 (circulation test): Eleven patients who expired in the intensive care unit (ICU), with arterial lines attached, received standard pre‐cordial cardiac massage, and the generated blood pressure (BP) was recorded. They were then turned to the prone position, with the head turned to one side. We compressed the patients thoracic spine with the same force used in standard CPR (rhythm of approximately 60 per minute each time when the back bounces back), and the BP was also recorded. Part 2 (ventilation test): Ten healthy volunteers (5 doctors and 5 nurses) were enlisted for respiratory assessment during compression on the back. With the nose clipped and spontaneous breathing held, the volunteers exhaled tidal volume upon compression was measured with a spirometer. Results: Standard external cardiac massage of the cadavers generated BPs of 55 ± 20/13 ± 7 mmHg; however, external compression on the back of the cadavers generated higher BP of 79 ± 20/17 ± 10 mmHg (p = 0.028, Wilcoxon signed‐rank analysis). External compression on the back of the volunteers generated mean tidal volumes of 399 ± 110 mL. Conclusion: Our study revealed that prone CPR provides good respiratory and circulatory support at the same time. It is easy to perform and it may be a good alternative way for bystanders to perform CPR in public surroundings. We recommend that more investigators do further studies on this topic.

The utilization of twelve-lead electrocardiography for predicting sudden cardiac death after heart transplantation

BACKGROUND Sudden cardiac death (SCD) occurs commonly after heart transplantation (HTX). The utilization of surface electrocardiography (ECG) to assess post-HTX SCD has not been investigated thoroughly. This study aimed to investigate the specific changes in surface ECG in HTX patients with SCD. METHODS A total of 227 HTX patients (age 48 ± 14 y/o, mean donor age 34 ± 14 y/o, 173 males) were followed up regularly at the outpatient clinic. Twelve-lead ECGs were recorded during 1-2 monthly visits. Serial ECG parameters and relevant clinical data were collected and analyzed. RESULTS During the follow-up period of 96 ± 51 months, SCD occurred in 28 (12.3%) patients. The baseline ECG parameters were comparable between patients with and without SCD. Important ECG trends of rising rest heart rates and prolongation of corrected QT (QTc) and JT (JTc) intervals were observed prior to development of SCD. After adjustment for other clinical variables, the independent predictors for SCD were older donor age (p = 0.014, OR 1.05, 95% CI 1.01-1.09), faster heart rate (p = 0.006, OR 1.06, 95% CI 1.02-1.1) and longer JTc interval (p = 0.015, OR 1.03, 95% CI 1.01-1.06). SCD occurred in 71.4% patients presenting with all three risk predictors. CONCLUSIONS Besides older donor age, important ECG signs, including prolongation of the JTc interval and increased heart rate during post HTX follow up, could predict SCD.

Malignant presentation of cardiac hemangioma: a rare cause of complete atrioventricular block.

A 46-year-old woman suffered effort intolerance for months. She had been healthy in the past, without systemic diseases. She had experienced near-syncope before arrival at our center. On admission, her physical examination was unremarkable. ECG exhibited normal sinus rhythm, P pulmonale, and first-degree atrioventricular (AV) block. A transthoracic echocardiogram demonstrated a huge right atrial (RA) mass, 7.98×5.70 cm in size, with 23 mm Hg of transvalvular pressure gradient. The global ventricular contractility was normal (Data Supplement Movies I and II). These findings were confirmed by 3-dimensional echocardiography (Figure 1; Data Supplement Movies III and IV). Cardiac magnetic resonance imaging showed a large, well-defined intracavity mass on T1-weighted image. After contrast injection, delayed images revealed a strong signal indicating hypervascularity (Figure 2 and online-only Data Supplement), highly suggestive …

Tricuspid Valve Regurgitation and Endomyocardial Biopsy After Orthotopic Heart Transplantation

OBJECTIVE Tricuspid valve regurgitation (TR) after heart transplantation (HTx) has been reported to be caused by endomyocardial biopsy (EMB), acute cellular rejection (ACR), or atrial anastomosis. We performed a prospective study of this problem among our HTx cohort. METHODS From 1988 to 2006, we performed 274 HTx. Excluding cases within 1 year (2006), there were 178 patients in whom we had records of EMB dates, ACR grades (International Society for Heart and Lung Transplantation [ISHLT], 1990), echocardiography-measured TR, and time-to-TR. Statistical analyses were performed using nonparametric comparisons, Spearman correlation, Kaplan-Meier time to failure curves, and Cox regression model. RESULTS All 178 patients underwent a biatrial anastomosis and underwent 2631 EMB (median, 15 times per patient; range, 0-42). The median follow-up duration was 66 months (range 2 days-194 months). Up to December 31, 2006, there were 47 patients (47/178 = 26.4%) who developed moderate-to-severe TR, which differed significantly from the prevalence rate (24/39 = 61.5%) reported by another cardiac team (P = .001) that performed bicaval anastomoses in half of the cases (20/39 = 51%). Our 1-, 3-, and 10-year Kaplan-Meier incidence rates of remarkable TR were 14.7% (10.2%-20.8%), 19.4% (14.2%-26.2%), and 36.3% (27.2%-47.3%), respectively. A positive correlation was shown between each patients EMB times and ACR but not TR grades, in terms of mean, maximum, or minimum over time (all P < .001 for null hypothesis of noncorrelation). Each patients EMB times and number of definite ACRs (> or = ISHLT grade II) did not differ significantly between the two groups of remarkable versus nonremarkable TR. Remarkable TR was negatively predicted by each patients EMB times (hazard ratio = 0.93; P = .010) but not by the ACR grades or the numbers of definite ACRs. CONCLUSION Our cohort demonstrated that biatrial anastomosis, ACR, or EMB were not associated with the risk of remarkable TR. The protective effect of EMB on remarkable TR needs further investigation.

The Ability of Live Three-Dimensional Transesophageal Echocardiography to Evaluate the Attachment Site of Intracardiac Tumors

In this study, a case of a right ventricular myxoma and a case of a right ventricular hemangioma are used to demonstrate the ability of live three‐dimensional transesophageal echocardiography (3DTEE) to assess the site of tumor attachment. Because 3DTEE has the ability to visualize desired structures in multiple planes, we defined the attached portion of the tumors and measured the en face view dimensions. In addition, the improved ability of 3DTEE to evaluate tissue characteristics allowed differentiation of the heterogeneous myxoma and highly vascular hemangioma. On the contrary, because two‐dimensional (2D) TEE only allows structures to be viewed in a 2D plane, the attachment site can be located but complete delineation and measurement of area is not possible. As surgical options become less invasive, accurate attachment site location and size will become more important to ensure complete excision. (Echocardiography 2011;28:1041‐1045)

Measurement of Human Erythrocyte C4d to Erythrocyte Complement Receptor 1 Ratio in Cardiac Transplant Recipients With Acute Symptomatic Allograft Failure

BACKGROUND Complement activation has been recognized as a contributing factor to cardiac allograft dysfunction. Combined measurement of erythrocyte C4d (E-C4d) and complement receptor 1 (E-CR1) are potential biomarkers to monitor complement activity in patients with autoimmune diseases. We conducted a prospective study using CR1-2B11 monoclonal antibody to detect the E-C4d to E-CR1 ratio among our cardiac transplant recipients with acute symptomatic allograft failure. MATERIALS AND METHODS Eight recipients with acute cardiac allograft failure and 72 healthy controls were included in this study. Levels of E-C4d and E-CR1 were measured by indirect immunofluorescence and flow cytometry. The results were utilized to determine the association between patient C4d staining, histological features, and clinical outcomes. RESULTS Eight patients with nine episodes of sudden onset of graft failure and suspected antibody-mediated rejection (AMR) were included in this study. One patient who received emergent mechanical circulatory support was treated with plasmapheresis for his unstable hemodynamic status. The mean pretreatment left ventricular ejection fraction was 30.3%. No histological study demonstrated cellular rejection or AMR in any patient. There were two patients with positive C4d immunostaining. Three patients had four episodes of acute rejection with sudden death at home. The mean E-C4d/E-CR1 ratio in the study group (n = 9) was 0.22 +/- 0.07, and 0.12 +/- 0.10 in the control group (n = 72). As comparing both groups, we found the ratios were significant higher in the study group (P = .0003). CONCLUSIONS Measurement of the E-C4d/E-CR1 ratio may be a noninvasive method for detecting acute rejection after cardiac transplantation.

Development of an Echocardiographic Method for Choosing the Best Fitting Single‐Pass VDD Lead

YIN, W.‐H., et al.: Development of an Echocardiographic Method for Choosing the Best Fitting Single‐Pass VDD Lead. To achieve stable single‐lead VDD pacing, a selection of the electrode with the optimal distance between the lead tip and the floating atrial dipole (AV distance [AVD]) is important. The authors hypothesized that the size of the right heart chambers may affect atrial sensing, and that measurement of their internal dimension at end‐diastole (RHIDd) in the apical four chamber view by transthoracic echocardiography may aid in choosing the proper AVD. Twenty‐six consecutive cases that had undergone VDD pacer implantation using the conventional chest X ray were examined retrospectively by the echocardiographic method. The chest x‐ray method properly selected a lead with optimal atrial sensing, defined as minimum P wave amplitude ≥ 1.0 mV, for only 20 (77%) of 26 patients. By comparing these results with their respective RHIDd, a cut‐off point of 13 cm was obtained that indicated a criterion for choosing the proper AVD. The indication was that if the RHIDd was ≥ 13 cm, a lead with an AVD of 15.5/16 cm should have been used; if the RHIDd was < 13 cm, a lead with an AVD of 13/13.5 cm should have been chosen. Using the echocardiographic method, all six patients who had suboptimal atrial sensing could be identified and classified as having missized (four undersized; two oversized) permanent leads. In conclusion, the described method provides a promising preoperative assessment of the best fitting electrode length in single lead VDD pacing. A prospective study is ongoing to verify its applicability.

The additional value of live/real-time three-dimensional transesophageal echocardiography over two-dimensional transesophageal echocardiography for assessing mitral regurgitation with eccentric jets

Background: Two‐dimensional transesophageal echocardiography (2D TEE) Doppler color flow imaging is the gold standard for assessing the severity of mitral regurgitation (MR). Severe MR with very eccentric jet may involve more than one mitral leaflet lesion and can be missed by 2D TEE. The purpose of this study was to assess the usefulness and the incremental value of real‐time three‐dimensional (RT 3D) TEE over 2D TEE findings in the evaluation of patients suffering eccentric MR with more than one mitral leaflet lesion. Methods: Intraoperative 2D TEE and RT 3D TEE examinations were performed on 168 patients with Carpenter II MR who underwent surgery. MR was defined as either central, free‐standing eccentric jet or very eccentric jet. 2D TEE and RT 3D TEE finding were compared with surgical findings. Results: Of these 168 MR patients, 25 patients (14.9%) had central jets and 143 patients (85.1%) had eccentric jets. Among 143 patients with eccentric jets, 47 patients (32.9%) had free‐standing eccentric MR jets, and 96 (67.1%) patients had very eccentric jets. 3D TEE diagnosed the severity and location of MR lesions correctly in all patients; this was not the case with 2D TEE, which had significant diagnostic misses in nine patients (9.4%, p < 0.001) having MR with very eccentric jets. These nine patients had lesions on both mitral leaflets, which were missed during 2D TEE examination owing to the highly turbulent flows produced by very eccentric jets from one mitral leaflet lesion and impinging the opposite mitral leaflet lesion. Conclusion: The severity of MR with very eccentric jet was more accurately and comprehensively assessed by 3D TEE than by 2D TEE. Therefore, intraoperative RT 3D TEE provides incremental information that is generally superior to 2D TEE in patients with complex MR due to very eccentric jets.

Cardiac Transplantation in Situs Inversus : Two Cases Reports

The challenge of heart transplantation in patients with situs inversus is reconstruction of the systemic venous return. Herein we have presented 2 cases of complex congenital heart disease with atriovisceral situs inversus. Both of the patients shared many common cardiac anomalies, such as a single ventricle, a single AV valve with severe regurgitation, and severe pulmonary stenosis. We completed the venous connection in 2 different ways. In the first case, the donor inferior vena cava (IVC) was anastomosed to the recipient left-sided IVC directly, making the heart slightly counterclockwise rotated. In the second case, the IVC venous reconnection was accomplished by a composite conduit made of recipient right atrium.