Transcatheter Closure of Congenital and Acquired Muscular Ventricular Septal Defects Using the Amplatzer® Device

Surgical closure of congenital or acquired [post-myocardial infarction (MI)] muscular ventricular septal defects (MVSD) is still associated with significant mortality and long-term morbidity.1,2 Different surgical approaches have been suggested, requiring either a right or left ventriculotomy.3,4 Over the past few years, devices designed originally for percutaneous closure of atrial septal defects or patent ductus arteriosus have been used to close MVSDs with variable degrees of successful closure and residual shunts.5–10 Lock et al.5 first reported the transcatheter occlusion of a VSD using an “umbrella” device. Recently, Amin et al. described a new device for catheter closure of MVSDs in a canine model.11 Thanopoulos et al. reported on their initial clinical experience in humans using this new muscular VSD occluder to close MVSD from the venous route with good results.12 They presented the first clinical applications of this device in children. Transcatheter occlusion of MVSDs with device implantation either in the catheterization laboratory or intraoperatively has been reported in selected cases.5,8–10 Encouraging results have been recently described with the use of the Amplatzer® VSD occluder device.12–15 Hijazi et al.13 reported the first experience of a large center such as the Chicago Children’s Hospital in closing MVSDs using the Amplatzer device. The authors reported 8 patients with a success rate of 100%, and concluded that this device is safe and effective for closure of these defects. Lee et al.15 reported the first occlusion of a post-MI VSD using the Amplatzer® device. They suggested this device as an alternative to late reoperation in recurrent post-MI VSD following patch repair. The goal of this study was to report the combined experience of 2 cardiac centers in the transcatheter occlusion of both congenital and acquired MVSDs. Methods The Amplatzer device. The Amplatzer® MVSD occluder (AGA Medical Corporation, Golden Valley, Minnesota) was used for closure in 30 patients and is described previously.7 Two patients with large MVSD post-MI required the Amplatzer® septal occluder for closure. The details of this device have been previously reported.16 Patient population. Between June 1998 and September 2000, thirty-two patients aged 1.5 months to 86 years (median, 11.5 years) underwent an attempted transcatheter closure of their MVSDs. Nineteen patients had congenital unoperated MVSDs, twelve had acquired MVSDs post-MI and 1 had an acquired MVSD post-surgical myomyectomy for hypertrophic cardiomyopathy. Among patients with post-MI MVSDs, three were treated in the acute phase of MI, five were treated for a residual post-surgical MVSD and 4 were in the chronic phase. All patients had left ventricular (LV) volume overload as documented by transthoracic echocardiography (TTE). One patient (#2) with large apical MVSD had pulmonary artery hypertension (blood pressure, 85/60 mmHg) and failure to thrive. Associated cardiac anomalies included coarctation of the aorta in 2 patients (#27 and #28); ASD and patent ductus arteriosus in 1 patient (#30) and pulmonary stenosis in 1 patient (#31). One patient (#12) was status post-pulmonary artery band for multiple ventricular septal defects. The mid-muscular VSD was closed in the catheterization laboratory and the next day the patient underwent surgical closure of a large inlet type VSD, debanding and reconstruction of the main pulmonary artery. The location of the VSD as assessed by TTE was mid-muscular in 14 patients, posterior in 10, apical in 5 and anterior in 3. The median size of the MVSD as assessed by TTE was 6.2 mm (range, 3–13 mm) and the median size as assessed by angiography was 7.1 mm (range, 4–16 mm). Qp/Qs ratio was calculated in 18 patients. The median ratio was 1.7 (range, 1.0–5.3). Informed consent was obtained in each case. Closure protocol. Patients were screened by conventional transthoracic 2-dimensional and color Doppler echocardiography. Two patients with suboptimal transthoracic examination were further evaluated with transesophageal echocardiography. Patients underwent right and left heart catheterization under general endotracheal anesthesia. The location of the defect was defined by axial angiographic views. To cross the VSD, two techniques were utilized. The first technique crossed the VSD from the left ventricular side with a 0.035´´ floppy J-tipped wire through a 4–6 Fr Judkins right coronary catheter. After crossing the VSD from the LV, a long wire formed a loop from the femoral artery, through the VSD and out the right internal jugular vein. A 6–9 Fr long Mullins type sheath (AGA Medical Corporation or Cook Incorporated, Bloomington, Indiana) was advanced from the right internal jugular vein through the VSD and into the LV. The second technique crossed the VSD from the right ventricle side, where a balloon-tipped catheter was advanced from the right internal jugular vein into the right ventricle and crossed the defect. Once in the left ventricle, a 6–9 Fr sheath was exchanged for that catheter over an extra-stiff exchange guidewire. In the Milan series, balloon sizing of the defect was performed to measure the stretched diameter of the defect. However, in the Chicago series, the angiographic diameter at end diastole was utilized to select the proper device size. Both fluoroscopy and echocardiography guided device deployment. After the device was released, both angiography and color Doppler echocardiography assessed the result of the closure. The total procedural time ranged from 83–323 minutes (median, 236 minutes) and the fluoroscopy time ranged from 11.7–146.0 minutes (median, 56.7 minutes). All patients received heparin (100 units/kg) and antibiotics during the procedure. Aspirin (5 mg/kg daily) was given after the procedure and for the following 6 months. All patients had a chest X-ray and a transthoracic color Doppler echocardiographic study at 24 hours post-procedure and at follow-up. Results Patients and MVSD characteristics are summarized in Table 1. In the Milan series, the balloon-stretched diameter of the MVSD ranged from 6–26 mm (mean, 11 ± 5 mm). The Qp/Qs ratio (calculated in 18 patients with congenital MVSD only) varied from 1.0–5.3 (median, 1.7). Since the Qp/Qs ratio did not influence the decision to treat patients with MI, the ratio was not calculated. Systolic pulmonary artery pressure was elevated (>= 30 mmHg) in 18 patients and was normal in the remainder of patients. In 5 patients (#17, #18, #20, #22 and #32), the MVSD was a residual defect following a previous surgical repair; in 1 patient (#27) with multiple MVSDs, the surgeon closed those defects amenable via the right atrium and left the most apical one for device closure. The Amplatzer® occluder devices were successfully delivered in 30 out of 32 patients. Patient #21 had 2 episodes of cardiac arrest during the procedure and died just before device release. Patient #26 was judged unsuitable for device closure due to the large size VSD; he died 2 days after the surgical closure. The devices were delivered from the internal jugular vein in the majority of patients. However, in patients #4, #5 and #8, the devices were delivered retrogradely from the femoral artery due to the location of the VSD and the difficulty advancing the device from the jugular vein to the VSD. In 2 very high-risk patients (#20 and #23) with large acquired defects, two Amplatzer septal occluder devices (sizes 26 mm and 20 mm) were deployed. Patient #28 had device malposition necessitating surgical device removal and closure of the defect 24 hours post-catheterization. Malposition of the right ventricular disc occurred in 1 patient (#28) and was successfully managed by recapturing and redeploying the device. Two patients had severe hemolysis; one of them (#20) died 3 days after implantation from severe cardiac failure. One patient (#4) developed transient junctional rhythm, requiring no treatment. Among the 30 patients with successful implantation, five died. Three patients died in the hospital (#19 in the catheterization laboratory due to tamponade, #20 during the first week post-procedure due to low cardiac output and #25 three days post-procedure due to progression of the infarct and rupture of the ventricular septum). Two patients died after hospital discharge (#15 died two weeks post-procedure due to a gastrointestinal hemorrhage and #18 died 35 days post-procedure in another hospital were he was admitted due to chest infection). Figures 1 and 2 are examples of 2 patients who received the device successfully. Follow-up data are available in all surviving patients with a maximum follow-up interval of 29 months. The device is in an appropriate position and not interfering with the adjacent cardiac structure in all patients. No evidence of residual shunt has been detected in any patient. Two patients (#2 and #22) underwent repeat cardiac catheterization documenting normal pulmonary artery pressure and no residual shunt. Discussion MVSD is an uncommon form of congenital heart disease and is also a serious complication following MI. Transcatheter occlusion of VSDs was first reported in 1988 by Lock at al.5 as an alternative to surgery. A variety of devices have been used for closure of congenital and acquired MVSDs; however, these devices were designed for catheter closure of atrial septal defects or patent ductus arteriosus and therefore have not always performed as expected for closure of muscular VSDs. In our experience, the Amplatzer® VSD occluder is the device of first choice for the following reasons: 1) it can be delivered through a 6–8 Fr sheath, extending the application of this method to small infants; 2) it can be easily repositioned and redeployed several times without destruction of the device; 3) it is made of Nitinol, a much more fatigue-resistant metal than stainless-steel; and 4) once the device is encased in fibrous tissue and endothelialized, it is unlikely that any possible fractured wires will protrude through tissue or embolize. An important question for catheter closure of MVSD is the timing or indication for closure. Most mid and apical congenital MVSDs are usually small and hemodynamically insignificant, requiring no treatment at all. Traditionally, calculation of Qp/Qs ratio of >= 1.5 is one of the indications for closure; however, this measurement is flawed. Therefore, although we measure this ratio, the most important criteria for closure are left ventricular volume overload and symptoms. Thanopoulos et al.7 reported MVSD closure in 6 patients with a Qp/Qs ranging from 1.7–2.5. Hijazi et al.8 reported on 8 patients with a Qp/Qs of 1.7 ± 0.6. In this series of patients in Milan and Chicago, the median Qp/Qs ratio was 1.7 (range, 1.0–5.3). The pathophysiology of acquired MVSD is different. Post-infarction VSD complicates approximately 1–2% of acute MI cases and accounts for about 5% of early death after MI.17 The abrupt rupture of the ventricular septum worsens significantly the prognosis for those who survive the MI. The closure of MVSD is often mandatory in order to reverse cardiogenic shock. Without MVSD closure, only 50% of patients survive after 1 week and less than 20% survive at 1 month post-MI. Hospital mortality following emergency surgical repair ranges from 60–100% depending on the pre-operative clinical characteristics of the patient population. Despite successful initial repair, MVSD recurs in 10–20% of patients.18 The residual defect may cause significant hemodynamic disturbance or hemolysis requiring reintervention. The morbidity and mortality after surgical repair of both congenital and acquired MVSDs remain significant.2,10 In our experience, good results could be predicted in patients with congenital MVSD undergoing transcatheter closure. However, in patients with acquired post-MI MVSD, the results are dependent on the timing of the closure. Among the 3 patients treated in the acute phase of infarction, one died during the procedure and 2 died during the first week after the procedure. Transcatheter closure of MVSD using an Amplatzer® VSD occluder appears to be a promising technique; however, long-term safety studies are required before this technique becomes widely used in routine clinical practice.

1. Serraf Lacour-Gayet F, Bruniaux J, Ouknine R, et al. Surgical management of isolated multiple ventricular septal defect. J Thorac Cardiovasc Surg 1992;103:437–443. 2. Movroudis C, Backer CL, Idriss FS. Pediatric Cardiac Surgery, Second Edition. St. Louis, Missouri: Mosby, 1994: pp. 201–224. 3. Shumacker HB. The repair of defects of the muscular portion of the ventricular septum. Surg Gynecol Obstet 1973;136:103–104. 4. Singh AK, de Leval MR, Stark J. Left ventriculotomy for closure of muscular ventricular septal defects. Ann Surg 1989;186:577–580. 5. Lock JE, Block PC, McKay RG, et al. Transcatheter closure of ventricular septal defects. Circulation 1988;78:361–368. 6. Sideris EB, Walsh KP, Haddad JL, et al. Occlusion of congenital ventricular septal defects by the buttoned device. Heart 1997;77:276–279. 7. Rigby ML, Redington AN. Primary transcatheter umbrella closure of perimembranous ventricular septal defect. Br Heart J 1994;72:368–371. 8. Murzi B, Bonanomi GL, Giusti S, et al. Surgical closure of muscular ventricular septal defects using double umbrella devices (intraoperative VSD device closure). Eur J Cardiothorac Surg 1997;12:450–455. 9. Benton JP, Barker KS. Transcatheter closure of ventricular septal defect: A non-surgical approach to the care of the patient with acute ventricular septal rupture. Heart Lung 1992;21:356–364. 10. Landzberg MJ, Lock JE. Transcatheter management of ventricular septal rupture after myocardial infarction. Semin Thorac Cardiovasc Surg 1998;10:128–132. 11. Amin Z, Gu X, Berry JM, et al. New device for closure of muscular ventricular septal defects in a canine model. Circulation 1999;100:320–328. 12. Thanopoulos BD, Tsaousis GS, Konstadopoulou GN, Zarayelyan AG. Transcatheter closure of muscular ventricular septal defects with the Amplatzer ventricular septal defect occluder: Initial application in children. J Am Coll Cardiol 1999;33:1395–1399. 13. Hijazi ZM, Hakim F, Fadley F, et al. Transcatheter closure of single muscular ventricular septal defects using the Amplatzer muscular VSD occluder: Initial results and technical considerations. Cathet Cardiovasc Intervent 2000;49:167–172. 14. Tofeig M, Patel RG, Walsh KP. Transcatheter closure of a mid-muscular ventricular septal defect with an Amplatzer VSD occluder device. Heart 1999;81:438–440. 15. Lee EM, Roberts DH, Walsh KP. Transcatheter closure of a residual post myocardial infarction ventricular septal defect with the Amplatzer septal occluder. Heart 1998;80:522–524. 16. Masura J, Gavora P, Formanek A, Hijazi ZM. Transcatheter closure of secundum atrial septal defects using the new self-centering Amplatzer septal occluder: Initial human experience. Cathet Cardiovasc Diagn 1997;42:388–393. 17. Madsen JC, Daggett WM Jr. Repair of postinfarction ventricular septal defects. Semin Thorac Cardiovasc Surg 1998;10:117–127. 18. Caputo M, Wilde P, Angelini GD. Management of postinfarction ventricular septal defect. Br J Hosp Med 1995;54:562–566.