Author + information
- Received September 12, 2011
- Revision received December 13, 2011
- Accepted January 5, 2012
- Published online April 1, 2012.
- Rong Yang, MD⁎ (, )
- Xiang-Qing Kong, MD,
- Yan-Hui Sheng, MD,
- Lei Zhou, MD,
- Di Xu, MD,
- Yong-Hong Yong, MM,
- Wei Sun, MD,
- Hao Zhang, MD and
- Ke-Jiang Cao, MD
- ↵⁎Reprint requests and correspondence:
Dr. Rong Yang, Department of Cardiology, First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, China
Objectives The aim of this study was to analyze the risk factors and mid-term outcomes associated with post-procedure heart blocks (PPHBs) after transcatheter closure of perimembranous ventricular septal defect (pmVSD).
Background The development of heart blocks remains a major challenge for transcatheter closure of pmVSD.
Methods Transcatheter closure of pmVSD was carried out in 228 patients. Electrocardiography and 24-h Holter monitoring were performed before the procedure, within 1 week after the procedure, then 1, 3, 6, and 12 months, and every year thereafter.
Results Thirty-three patients (14.5%) who received transcatheter closure of pmVSD developed PPHBs. PPHBs included right bundle branch block (57.6%), left bundle branch block (24.2%), and atrioventricular block (18.2%). High-degree atrioventricular blocks occurred in 4 patients and recovered to normal conduction after intravenous administration of hydrocortisone. PPHBs recovered to normal conduction in 21 patients by the time of hospital discharge. Compared with the patients without PPHBs, the patients suffering PPHBs were characterized by a significantly longer distance between the aortic valve and the defect (DAVD), a shorter distance from the lower rim of the defect to the septal leaflet of the tricuspid valve (DLRD-SLTV), and a larger diameter difference between the occluder and ventricular septal defect (DDOV). The earlier the PPHBs developed after the procedure, the more difficult the recovery to normal conduction.
Conclusions The outcome of PPHBs after transcatheter closure of pmVSD was satisfactory, as most patients recovered to normal conduction. Measurements of DLRD-SLTV, DAVD, and DDOV may be useful in predicting the incidence of PPHBs.
Percutaneous device closure of perimembranous ventricular septal defect (pmVSD) has shown great promise since the year 2002 as a viable alternative to surgical closure (1–8). However, a relatively high incidence of post-procedure heart blocks (PPHBs) has also incurred attention, as they affect the safety of the procedure and the prognosis of patients (2,5,9–16). The exact incidence of PPHBs (mainly, bundle branch block and atrioventricular block [AVB]) remains unclear. In addition, there is a lack of reports describing risk factors and outcomes for PPHBs, which would be especially useful for comparing transcatheter approaches with other procedures, such as surgical repair. An analysis of risk factors for PPHBs would also be useful toward reducing the incidence of PPHBs.
The aim of this study was to determine the incidence, risk factors, and outcomes for PPHB after transcatheter closure of pmVSD.
Between January 2003 and December 2007, 244 patients underwent transcatheter closure of a pmVSD. Besides the requirements for ≥8-kg body weight and the presence of a left-to-right shunt, all inclusion criteria depended on the results of transthoracic echocardiography: ≤16-mm ventricular septal defect (VSD) diameter, distance from the aortic valve to the upper rim of the VSD ≥1 mm, a 9- to 11-o'clock position of the defect across the short-axis parasternal view, and <70 mm Hg of pulmonary pressure. Eventually, 228 patients (123 male, 105 female) successfully underwent transcatheter closure of pmVSD. The median age was 14.1 years (range: 1.5 to 60 years), and the median weight was 38.9 kg (range: 11 to 89 kg). The procedure was unsuccessful in 16 patients due to high atrioventricular block, aortic regurgitation, or a moderate residual shunt. These 16 patients underwent surgical closure eventually.
The local regulatory board of the First Affiliated Hospital of Nanjing Medical University approved this study. All the patients gave written informed consent before the procedure.
Percutaneous device closure of pmVSD
The devices used in this study were the Amplatzer asymmetrical ventricular septal occluder (AVSDO) (AGA Medical, Golden Valley, Minnesota) and the symmetrical ventricular septal occluder (SVSDO) (Lifetech Scientific, Shenzhen, China) (2). These 2 devices are self-expandable double-disk devices made of nitinol wire mesh. The connecting waist (1.5-mm long) and right ventricle disk (4-mm larger than the waist) of these 2 devices are the same. The only difference between the 2 devices is the shape of the left disk. In the AVSDO, the aortic end of the left ventricle disk is 0.5 mm larger than the waist, and the other end is 5.5 mm larger than the waist, whereas in the SVSDO, the diameter of the left disk is uniformly 4 mm larger than the waist (2).
The implantation technique for these devices has been described in detail previously (1,2). If the distance from the aortic valve to the defect was <2 mm, AVSDO was selected. Otherwise, AVSDO or SVSDO was randomly used. Briefly, the procedure was performed under general anesthesia with transthoracic echocardiography and fluoroscopic guidance. Standard right and left cardiac catheterization and left ventricular angiography in long axial oblique view (60° left anterior oblique/20° cranial) were performed to measure the pmVSD size and distance from the aortic valve to the defect (DAVD) (Figs. 1 and 2)⇓⇓ in all patients. The size of either selected device was >1 mm larger than the measured pmVSD size. After establishment of the femoral arterial and venous access port, heparin (100 IU/kg) was infused intravenously. The selected device was gradually released out of the sheath when it was delivered to the site of the pmVSD. All patients underwent left ventricular angiography before and after delivery of the device to ensure closure of the defect. If there were no complications, patients were discharged 7 days after the procedure and kept on oral aspirin (5 mg/kg daily) for 6 months.
All patients underwent electrocardiography, 24-h Holter monitoring, and transthoracic echocardiography before and after the procedure. Follow-up examinations were performed on an outpatient basis and scheduled at 1, 3, 6, and 12 months and yearly thereafter. None of the patients admitted to the hospital post-procedure were on continuous telemetry (including ambulatory telemetry).
Electrocardiography and 24-h Holter monitoring
Electrocardiography was performed in all patients before and every day after the procedure during their hospitalization. All patients also underwent 24-h Holter monitoring before and on the fifth day after the procedure. In addition, if patients developed PPHBs, a 24-h Holter test was carried out again on the fifth day after its development.
The criteria for a diagnosis of a PPHB (i.e., AVB or bundle branch block) were: 1) the heart block developed exclusively after placement of the selected device, whereas there had been no heart block before the procedure; or 2) if there did exist a heart block before the procedure, newly developed heart blocks after the procedure were different.
Transthoracic echocardiography was performed for each patient to measure the left ventricular end-diastolic dimension and the distance from the lower rim of the defects to the septal leaflet of the tricuspid valve (DLRD-SLTV) before and after the procedure.
Data were expressed as mean ± SD and analyzed with SPSS software version 11.0 (IBM, Armonk, New York). Differences of measured data were compared using the Student t test and the Wilcoxon rank sum test if heterogeneity of variance existed. Differences in categorical data were analyzed with the chi-square test. A p value < 0.05 was considered statistically significant. Predictors of PPHBs were determined by a multivariate stepwise logistic regression.
Heart blocks after procedure
PPHBs occurred in 33 cases (14.5%, 33 of 228) after the procedure (Table 1). The average time between device placement and development of PPHBs was 3.0 ± 1.6 days. Among these cases, right bundle branch block (RBBB) was the most common type (19 of 33, 57.6%), followed by left bundle branch block (LBBB) 8 of 33, 24.2%) and AVB (6 of 33, 18.2%). Among patients with procedure-induced AVB, 3 patients had third-degree AVB and 1 patient had second-degree Mobitz type 2 AVB (Table 1). The 3 cases with third-degree AVB developed progressively from either a complete RBBB with a left anterior hemiblock or a complete LBBB with a first-degree AVB. High-degree AVB in all these 4 patients reverted to the normal sinus rhythm after administration of intravenous hydrocortisone and application of a temporary pacemaker. Among the 33 patients suffering from PPHBs, recovery to normal conduction before discharge occurred in 21 cases, whereas PPHBs in the remaining 12 cases (2 with LBBB, 10 with RBBB) did not successfully recover by the time of discharge. In addition, 26 patients had heart blocks before the procedure (10 with RBBB, 11 with left anterior hemiblock, and 5 with first-degree AVB). Two patients with left anterior hemiblock before the procedure developed RBBB afterward. The other 24 patients did not develop PPHBs.
The mean follow-up time was 56.8 ± 14.0 months (range: 36 to 84 months). One hundred eighty-five patients (83.4%, 191 of 228) completed follow-up; 37 patients were lost to follow-up. All the 33 patients with PPHBs completed follow-up. Among the 12 patients with PPHBs at discharge, recovery to normal conduction occurred in 2 patients (1 with LBBB, 1 with RBBB) by the 1-month follow-up visit, and 1 patient (RBBB) by the 3-month follow-up visit.
One patient (45 years old) was implanted with an oversized occluder (28 mm) to occlude his large VSD (18.2 mm; the VSD with a ventricular septal aneurysm formation) during surgery. This patient was 1 of the 4 patients who developed a high-degree AVB after the procedure and recovered to normal conduction before discharge. He developed a high-degree AVB again 42 months after the procedure and was implanted with a permanent pacemaker.
Risk factors of PPHB
DAVD was significantly longer (3.9 ± 1.3 mm vs. 3.2 ± 1.5 mm) and DLRD-SLTV (2.3 ± 0.6 mm vs. 3.8 ± 1.6 mm) was significantly shorter in patients who developed PPHBs than those who did not (Table 2). The diameter difference between the occluder and ventricular septal defect (DDOV) was significantly larger in patients with PPHBs than in patients without it (3.5 ± 1.5 mm vs. 2.0 ± 0.7 mm, p < 0.05). In the logistic regression model, the following parameters were independent predictors of PPHBs: increasing DAVD (odds ratio [OR]: 1.88, p = 0.01; 95% confidence interval [CI]: 1.14 to 3.12), increasing DDOV (OR: 15.23, p < 0.01; 95% CI: 4.97 to 46.70), and decreasing DLRD-SLTV (OR: 0.33, p < 0.01; 95% CI: 0.18 to 0.59) (Table 3).
Risk factors for continuance of PPHBs after transcatheter closure of pmVSD
PPHBs occurred earlier in those patients whose PPHBs did not recover to normal conduction (Table 4). In the logistic regression model, the time of PPHB emergence was an independent predictor of PPHB persistence (OR: 0.03, p = 0.02; 95% CI: 0.00 to 0.52) (Table 5).
Since 2002, percutaneous techniques and devices have been developed specifically for the closure of pmVSD. The success rate of transcatheter closure of pmVSD has increased significantly, whereas complications, such as aortic or tricuspid regurgitation and device motion, decreased significantly (4–7,13,17–19). However, the incidence of heart blocks after closure of pmVSD has remained high, with complete AVB being the worst type (2,8–16). As a result, this method has not been widely accepted.
In this study, 14.5% of patients developed PPHBs. Among them, RBBB was the most common type of PPHB (57.6%), followed by LBBB and AVB. RBBB may be the most common type because the right bundle branch is spindly and easily damaged. However, most PPHBs reverted to normal conduction. High-degree AVB is the most serious PPHB. Four patients developed high-degree AVB (1.8%) in our study; its incidence has ranged from 1.1% to 5.7% in other reports (2,5–7,13,14,17). In addition, other types of PPHBs, including RBBB, LBBB, and first-degree AVB, could progress to high-degree AVB (9,10,17,20).
Most PPHBs, including high-degree AVB, were transient after closure of pmVSD and could recover to normal conduction spontaneously or by treatment with intravenous hydrocortisone and a temporary pacemaker (8–10,17,21). In practice, PPHBs occurred most frequently 2 to 7 days after device closure of pmVSD (4,6,7,9,10,15–18), but sometimes may also occur 2 to 4 weeks or even later (i.e., 12 to 36 months later) (4–6,9–11,14–16). As a result, patients should be closely observed for at least 7 days in the hospital and during follow-up visits.
In this study, a shorter DLRD-SLTV (OR: 0.33) or longer DAVD (OR: 1.88) were identified as risk factors for PPHBs. Our study showed that the likelihood of PPHBs increased the closer the VSD was to the tricuspid valve, or the farther it was from the aortic valve. This may be related to the conduction system crossing through the nearby tricuspid valve. If the location of the VSD is close to the tricuspid valve, the device may disturb atrioventricular conduction by direct traumatic compression. Furthermore, the device may give rise to an inflammatory reaction or scar formation in the conduction tissue. An oversized device (OR: 15.23) was another risk factor associated with the occurrence of PPHBs in our study, as has also been reported elsewhere (6,7).
Our study showed that the earlier a PPHB developed after closure of the pmVSD, the more difficult was a recovery to normal conduction. It is notable that for patients whose PPHBs did not recover to normal, it may have been due to the immediate effect of compression of the conduction system by the VSD occluder (22).
The incidence of PPHBs after transcatheter closure of pmVSD is relatively high, but the outcome of PPHBs after transcatheter closure of pmVSD was satisfactory, as most patients recovered to normal conduction. More careful monitoring after transcatheter closure of pmVSD should be applied for patients whose pmVSD is close to the tricuspid valve and far away from the aortic valve. Oversized devices should be avoided.
The authors have reported that they have no relationships relevant to the contents of this paper to disclose. Drs. Yang and Kong contributed equally to this work.
- Abbreviations and Acronyms
- atrioventricular block
- asymmetrical ventricular septal occluder
- confidence interval
- distance from the aortic valve to the defect
- diameter difference between the occluder and ventricular septal defect
- distance from lower rim of the defects to the septal leaflet of the tricuspid valve
- left bundle branch block
- odds ratio
- perimembranous ventricular septal defect
- post-procedure heart block
- right bundle branch block
- size of device
- symmetrical ventricular septal occluder
- ventricular septal defect
- Received September 12, 2011.
- Revision received December 13, 2011.
- Accepted January 5, 2012.
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