Displaying publications 1 - 20 of 41 in total

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  1. Alwi M
    Future Cardiol, 2012 Mar;8(2):237-50.
    PMID: 22413983 DOI: 10.2217/fca.12.4
    Maintaining ductal patency in duct-dependent congenital heart lesions by implantation of coronary stents is an alternative to systemic pulmonary shunt in selected cases and lesions with suitable anatomy. This article focuses on the procedure as the initial palliation in duct-dependent pulmonary circulation, its associated pitfalls and complications. A good understanding of the diverse duct morphology is paramount prior to stenting of the ductus. Long tortuous duct, insufficiently constricted ductus at the pulmonary end and ductus with associated branch pulmonary artery stenosis at the site of insertion are not suitable for stenting. Durability of palliation is generally inferior to a surgical shunt and this may dictate earlier definitive surgical repair. Acceleration of branch pulmonary artery stenosis in certain ductal morphology limits its general applicability. Bioabsorbable and biodegradable stents may offer some solution to this problem.
  2. Alwi M
    Ann Pediatr Cardiol, 2008 Jan;1(1):38-45.
    PMID: 20300236 DOI: 10.4103/0974-2069.41054
    Ductal stenting is an attractive alternative to conventional shunt surgery in duct dependent congenital heart disease as it avoids thoracotomy and its related problems. With today's generation of coronary stents which have better profile, flexibility and trackability, ductal stenting may be achieved safely and with considerably less difficulty than previously described.As in Blalock-Taussig (BT) shunt, ductal stenting is indicated mainly in duct-dependent cyanotic lesions chiefly in the neonatal period. Unlike the Patent ductus arteriosus (PDA) as an isolated lesion, the ductus in cyanotic heart disease has a remarkable morphologic variability. The ductus tends to arise more proximally under the aortic arch, giving rise to a vertical ductus or occasionally it may arise from the subclavian artery. It also tends to be long and sometimes very tortuous, rendering stent implantation technically impossible. The ductus in these patients may also insert onto one of the branch pulmonary arteries with some stenosis at the site of insertion. The ductus in Tetralogy of Fallot with pulmonary atresia (TOF-PA) tend to exhibit these morphologic features and to a lesser degree in transposition of great arteries with ventricular septal defect and pulmonary atresia (TGA-VSD-PA) and the more complex forms of univentricular hearts. In the preliminary angiographic evaluation, it is important to delineate these morphologic features as the basis for case selection.Ductal stenting may be done by the retrograde femoral artery route or the antegrade transvenous route depending on the ductus morphology and the underlying cardiac lesion. The detailed techniques and essential hardware are described. Finally, major potential complications of the procedure are described. Acute stent thrombosis is the most serious and potentially catastrophic. Emergent treatment with thrombolytic therapy and mechanical disruption of thrombus are required. With proper case selection, appropriate technique and the right hardware ductal stenting provides reasonable short-medium term palliation in duct-dependent cyanotic heart disease.
  3. Adeeb SMSJ, Leman H, Sallehuddin A, Yakub A, Awang Y, Alwi M
    Med J Malaysia, 2004 Mar;59(1):11-4.
    PMID: 15535329
    This retrospective study illustrates our approach to this problem over the years, from performing subclavian flap aortoplasty initially to the more accepted procedure now, which is resection and end-to-end anastomosis. Coarctation of aorta in our population is seen in a varying age groups and are also associated with other cardiac anomalies including both acyanotic and cyanotic congenital cardiac defects. Therefore a wide variety of surgical procedures were performed including resection of the coarcted segment and end-to-end anastomosis, subclavian flap aortoplasty, patch aortoplasty and synthetic tube graft interposition. Subclavian flap aortoplasty is not widely practised anymore in favour of resection with end-to-end anastomosis. Fifty four point four percent of patients had isolated coarctation, 10.5% had associated valvular defects, 28.1% had other simple congenital defects and 7.0% had associated complex cyanotic congenital defects. Perioperative mortality was 5.26% and is correlated with the younger age of patients at time of surgery and severity of cardiac failure at time of presentation. We did not see any difference in mortality for patients with complex congenital disease or between the different surgical procedures. However, we did find that in the early period when resection with end-to-end anastomosis was performed, there was a significantly higher incidence of morbidities.
  4. Latiff HA, Samion H, Kandhavel G, Aziz BA, Alwi M
    Cardiol Young, 2001 Mar;11(2):201-4.
    PMID: 11293739
    BACKGROUND: From January, 1997, as part of an international multicentric trial, we have been closing small-to-moderate atrial septal defects within the oval fossa using the Amplatzer Septal Occluder (ASO, AGA Medical).

    METHODS: All patients with defects within the oval fossa deemed potentially suitable for transcatheter closure were investigated by transesophageal echocardiography with the aim of gaining extra information that might alter the decision to use the device to close the defect. Views were obtained in transverse and longitudinal planes, permitting measurements of the diameter of the defect, and its distance from the atrioventricular valves, coronary sinus, and pulmonary veins. Additionally, we sought to identify multiple defects, and to exclude sinus venosus defects.

    RESULTS: Of 56 patients with left-to-right shunts, 41 (73.2%) were deemed suitable for closure with the Amplatzer Septal Occluder. All underwent the procedure successfully, with no complications. This includes 5 patients with multiple small defects that were sufficiently close to the main defect to be closed with a single device. Only two of these had been detected on the transthoracic study. In the remaining 15 of 56 patients, transcatheter closure was deemed unsuitable. In 9 patients, this was due to the limitation of the size of the device available during the period of study, this representing a relative contraindication. In the remaining 6 (10.7%), transcatheter closure was not performed because multiple defects were too far apart to be closed with a single device in 3 patients, two patients were noted to have a sinus venosus defect, and another was noted to have anomalous connection of the right upper pulmonary vein to the right atrium. Excluding patients contraindicated due to the size of the defect alone, transesophageal echocardiography provided extra information in one-tenth of our patients, which altered the decision regarding management.

    CONCLUSION: Transesophageal echocardiography is indispensable in the evaluation of patients undergoing transcatheter closure of atrial septal defect.

  5. Abdul Aziz B, Alwi M
    Catheter Cardiovasc Interv, 1999 Oct;48(2):191-3.
    PMID: 10506777
    We report a case of a 14-month-old-infant with severe congenital mitral stenosis who presented with pulmonary oedema, acute renal failure and haemodynamic instability. Balloon dilatation was successfully performed under fluoroscopic and transesophageal echocardiographic guidance. Cathet. Cardiovasc. Intervent. 48:191-193, 1999.
  6. Chan KC, Alwi M
    Med J Malaysia, 1987 Jun;42(2):97-103.
    PMID: 3503198
    Eleven consecutive cases of simple transposition of great arteries were palliated by balloon atrial septostomy, The arterial saturation was improved and the gradient across the atrial septum was reduced or abolished. Improvement in the clinical status was achieved in all the patients. There was no mortality and morbidity was mild. A description of the technique as well as a brief review of the anatomy and haemodynamics of complete transposition of great arteries are the aims of this paper.
  7. Leong MC, Ahmed Alhassan AA, Sivalingam S, Alwi M
    Ann Thorac Surg, 2019 09;108(3):813-819.
    PMID: 30998905 DOI: 10.1016/j.athoracsur.2019.03.045
    BACKGROUND: Ductal stenting is performed to retrain involuted left ventricles (LVs) in patients with d-transposition of the great arteries and intact ventricular septum (TGA-IVS). However, its efficacy is largely unknown. This study aimed to determine the safety and efficacy of ductal stenting in retraining of the involuted LV in patients with TGA-IVS.

    METHODS: This was a single-center, retrospective study. Echocardiographic assessment of the LV geometry, mass, and free wall thickness was performed before stenting and before the arterial switch operation. Patients then underwent the arterial switch operation, and the postoperative outcomes were reviewed.

    RESULTS: There were 11 consecutive patients (male, 81.8%; mean age at stenting, 43.11 ± 18.19 days) with TGA-IVS with involuted LV who underwent LV retraining by ductal stenting from July 2013 to December 2017. Retraining by ductus stenting failed in 4 patients (36.3%). Two patients required pulmonary artery banding, and another 2 had an LV mass index of less than 35 g/m2. Patients in the successful group had improved LV mass index from 45.14 ± 17.91 to 81.86 ± 33.11g/m2 (p = 0.023) compared with 34.50 ± 10.47 to 20.50 ± 9.88 g/m2 (p = 0.169) and improved LV geometry after ductal stenting. The failed group was associated with an increased need for extracorporeal support (14.5% vs 50%, p = 0.012). An atrial septal defect-to-interatrial septum length ratio of more than 0.38 was associated with failed LV retraining.

    CONCLUSIONS: Ductal stenting is an effective method to retrain the involuted LV in TGA-IVS. A large atrial septal defect (atrial septal defect-to-interatrial septum length ratio >0.38) was associated with poor response to LV retraining.

  8. Leong MC, Alwi M
    Cardiol Young, 2021 May 31.
    PMID: 34053471 DOI: 10.1017/S1047951121001980
    Device occlusion of perimembranous ventricular septal defect is gaining popularity with the emergence of newer, softer occluders and improved technical know-how. We report a 26-year-old lady with a moderate size perimembranous ventricular septal defect who had a new onset of bundle branch block shortly after device closure. The patient subsequently developed a complete atrio-ventricular heart block.
  9. Hayashi T, Akhtar S, Alwi M
    Ann Pediatr Cardiol, 2017 6 2;10(2):206-208.
    PMID: 28566833 DOI: 10.4103/0974-2069.205143
    We report our experience with a stent migration after right ventricle outflow tract stenting and converted to patent ductus arteriosus stenting in Tetralogy of Fallot (TOF) with severe infundibular stenosis. Finally, the patient achieved to TOF repair, and the migrated stent was removed without any complication.
  10. Elarabi AI, Leong MC, Alwi M
    Ann Pediatr Cardiol, 2017 6 2;10(2):203-205.
    PMID: 28566832 DOI: 10.4103/0974-2069.205157
    We report an 8-year-old male child with tetralogy of Fallot (TOF), who developed left pulmonary artery (LPA) atresia, following surgical repair of TOF and left pulmonary arterioplasty at the age of 6 years. He underwent successful radiofrequency recanalization and stenting of the LPA. The LPA exhibited satisfactory growth for 3 months, following recanalization and stenting.
  11. Alwi M
    Catheter Cardiovasc Interv, 2006 May;67(5):679-86.
    PMID: 16572430 DOI: 10.1002/ccd.20672
    Pulmonary atresia with intact ventricular septum (PAIVS) is a disease with remarkable morphologic variability, affecting not only the pulmonary valve but also the tricuspid valve, the RV cavity and coronary arteries. With advances in interventional techniques and congenital heart surgery, the management of PAIVS continues to evolve. This review is an attempt at providing a practical approach to the management of this disease. The basis of our approach is morphologic classification as derived from echocardiography and angiography. Group A, patients with good sized RV and membranous atresia, the primary procedure at presentation is radiofrequency (RF) valvotomy. Often it is the only procedure required in this group with the most favourable outcome. Patients with severely hypoplastic RV (Group C) are managed along the lines of hearts with single ventricle physiology. The treatment at presentation is patent ductus arteriosus (PDA) stenting with balloon atrial septostomy or conventional modified Blalock Taussig (BT) shunt. Bidirectional Glenn shunt may be done 6-12 months later followed by Fontan completion after a suitable interval. Patients in Group B, the intermediate group, are those with borderline RV size, usually with attenuated trabecular component but well developed infundibulum. The treatment at presentation is RF valvotomy and PDA stenting +/- balloon atrial septostomy. Surgical re-interventions are not uncommonly required viz. bidirectional Glenn shunt when the RV fails to grow adequately (11/2 - ventricle repair) and right ventricular outflow tract (RVOT) reconstruction for subvalvar obstruction or small pulmonary annulus. Catheter based interventions viz. repeat balloon dilatation or device closure of patent foramen ovale (PFO) may also be required in some patients.
  12. Lee J, Sivalingam S, Alwi M
    Ann Pediatr Cardiol, 2017 9 21;10(3):281-283.
    PMID: 28928615 DOI: 10.4103/apc.APC_168_16
    We report a case of Tetralogy of Fallot with severe cyanosis who underwent a successful right ventricular outflow tract stenting. Follow-up echocardiography revealed moderate aortic regurgitation due to the impingement of the stent on the aortic valve. The patient underwent successful surgical correction at which time the stent was removed completely with a resolution of the aortic regurgitation.
  13. Rehman R, Marhisham MC, Alwi M
    Future Cardiol, 2018 01;14(1):55-73.
    PMID: 29199861 DOI: 10.2217/fca-2017-0053
    Patent ductus arteriosus (PDA) stenting has gained acceptance for palliation in cyanotic congenital heart disease. The PDA in tetralogy of Fallot with pulmonary atresia (ToF-PA) arises, in the left aortic arch, from underneath the arch and connects to the proximal left pulmonary artery, often resulting in stenosis. The PDA is usually elongated and tortuous, making stent implantation challenging. Shorter duration of palliation, aggravation of branch pulmonary artery stenosis resulting in poor growth and difficulty at surgery makes ductal stenting controversial. Access via the carotid and axillary artery reduces complexity of the procedure and improves success, with recent data demonstrating good pulmonary artery growth. Advances in bioresorbable stents offer future promise and will likely resolve some controversies surrounding PDA stenting in ToF-PA.
  14. Leong MC, Hoo XY, Alwi M
    Cardiol Young, 2024 Jan;34(1):228-231.
    PMID: 38073568 DOI: 10.1017/S1047951123004055
    Amplatzer Vascular Plug IV (Abbott, USA) is usually used for the occlusion of abnormal tortuous vessels and has not been tried for the transcatheter closure of perimembranous ventricular septal defects with wind-sock morphology. Here, we report on three successful cases of perimembranous ventricular septal defect transcatheter closure using Amplatzer Vascular Plug IV. We did not observe residual shunting or new onset of complications during follow up. These preliminary positive results advocate the application and suitability of Amplatzer Vascular Plug IV for closing wind-sock-like perimembranous ventricular septal defects.
  15. Shen D, Qi H, Lin W, Zhang W, Bian D, Shi X, et al.
    Sci Adv, 2021 Jun;7(23).
    PMID: 34088662 DOI: 10.1126/sciadv.abf0614
    Balancing the biodegradability and mechanical integrity of a bioresorbable scaffold (BRS) with time after implantation to match the remodeling of the scaffolded blood vessel is important, but a key challenge in doing so remains. This study presents a novel intercalated structure of a metallic BRS by introducing a nanoscale Zn sacrificial layer between the nitrided Fe platform and the sirolimus-carrying poly(d,l-lactide) drug coating. The PDLLA-Zn-FeN BRS shows a multistage biodegradation behavior, maintaining mechanical integrity at the initial stage and exhibiting accelerated biodegradation at the subsequent stage in both rabbit abdominal aortas and human coronary arteries, where complete biodegradation was observed about 2 years after implantation. The presence of the nanoscale Zn sacrificial layer with an adjustable thickness also contributes to the tunable biodegradation of BRS and allows the reduction of the metallic strut thickness to 53 μm, with radial strength as strong as that of the current permanent drug-eluting stents.
  16. Bilkis AA, Alwi M, Hasri S, Haifa AL, Geetha K, Rehman MA, et al.
    J Am Coll Cardiol, 2001 Jan;37(1):258-61.
    PMID: 11153748 DOI: 10.1016/s0735-1097(00)01094-9
    Objectives: The aim of the study was to assess the safety and efficacy of the Amplatzer ductal occluder (ADO) in transcatheter occlusion of patent ductus arteriosus (PDA).
    Background: Transcatheter closure of small to moderate sized PDAs is an established procedure. The ADO is a self-expandable device with a number of salutary features, notably its retrievability, ease of delivery via small 5F to 7F catheters and a range of sizes suitable even for the larger PDAs.
    Methods: Between November 1997 and August 1999, the ADO was successfully implanted in 205 of 209 patients with PDA. The inclusion criteria for this device occlusion method were patients with clinical and echocardiographic features of moderate to large PDA, weighing > or =3.5 kg as well as asymptomatic adolescents and adults with PDA measuring > or =5.0 mm on two-dimensional (2D) echocardiogram. Occlusion was achieved via the antegrade venous approach. Follow-up evaluations were performed with 2D echocardiogram, color-flow mapping and Doppler measurement of the descending aorta and left pulmonary artery velocity at 24 h and 1, 3, 6 and 12 months after implantation.
    Results: Two hundred and five patients had successful PDA occlusion using this device. The patients were between two months and 50 years (median 1.9) and weighed between 3.4 kg and 63.2 (median 8.4). Infants made up 26% of the total patients. The PDA measured from 1.8 to 12.5 mm (mean 4.9) at the narrowest diameter. Forty-four percent of patients achieved immediate complete occlusion. On color Doppler the closure rates at 24 h and 1 month after implant were 66% and 97%, respectively. At 6 and 12 months all except one patient attained complete occlusion. Device embolization occurred in three patients; in two this was spontaneous, and in the other it was due to catheter manipulation during postimplant hemodynamic measurement. Mild aortic narrowing was seen in an infant.
    Conclusions: Patent ductus arteriosus occlusion using ADO is safe and efficacious. It is particularly useful in symptomatic infants and small children with relatively large PDA. Embolization can be minimized by selection of appropriate sized devices, and caution should be exercised in infants <5 kg.
  17. Alwi M, Choo KK, Radzi NA, Samion H, Pau KK, Hew CC
    J. Thorac. Cardiovasc. Surg., 2011 Jun;141(6):1355-61.
    PMID: 21227471 DOI: 10.1016/j.jtcvs.2010.08.085
    Objectives: Our objective was to determine the feasibility and early to medium-term outcome of stenting the patent ductus arteriosus at the time of radiofrequency valvotomy in the subgroup of patients with pulmonary atresia with intact ventricular septum and intermediate right ventricle.
    Background: Stenting of the patent ductus arteriosus and radiofrequency valvotomy have been proposed as the initial intervention for patients with intermediate right ventricle inasmuch as the sustainability for biventricular circulation or 1½-ventricle repair is unclear in the early period.
    Methods: Between January 2001 and April 2009, of 143 patients with pulmonary atresia and intact ventricular septum, 37 who had bipartite right ventricle underwent radiofrequency valvotomy and stenting of the patent ductus arteriosus as the initial procedure. The mean tricuspid valve z-score was -3.8 ± 2.2 and the mean tricuspid valve/mitral valve ratio was 0.62 ± 0.16.
    Results: Median age was 10 days (3-65 days) and median weight 3.1 kg (2.4-4.9 kg). There was no procedural mortality. Acute stent thrombosis developed in 1 patient and necessitated emergency systemic-pulmonary shunt. There were 2 early in-hospital deaths owing to low cardiac output syndrome. One late death occurred owing to right ventricular failure after the operation. Survival after the initial procedure was 94% at 6 months and 91% at 5 years. At a median follow-up of 4 years (6 months to 8 years), 17 (48%) attained biventricular circulation with or without other interventions and 9 (26%) achieved 1½-ventricle repair. The freedom from reintervention was 80%, 68%, 58%, and 40% at 1, 2, 3, and 4 years, respectively.
    Conclusions: Concomitant stenting of the patent ductus arteriosus at the time of radiofrequency valvotomy in patients with pulmonary atresia with intact ventricular septum and intermediate right ventricle is feasible and safe with encouraging medium-term outcome.
  18. Abdelbasit MA, Alwi M, Kandavello G, Che Mood M, Samion H, Hijazi ZM
    Catheter Cardiovasc Interv, 2015 Jul;86(1):94-9.
    PMID: 25675888 DOI: 10.1002/ccd.25878
    OBJECTIVES: To evaluate the feasibility, safety, and efficacy of the Occlutech® PDA occluder for closure of patent ductus arteriosus (PDA).

    BACKGROUND: The Occlutech® PDA occluder is novel, self-shaping Nitinol wire device with PET (polyethylene terephthalate) patches integrated into the shank of the device to assure a better obturation of the ductus. The Occlutech® PDA occluder has undergone two design modifications.

    METHODS: A prospective, non-randomized pilot study was started in November 2011. Thirty-three patients were included until April 2013. Patients weighing <6 kg or those with associated cardiac anomalies that required surgery were excluded. All patients were followed up by transthoracic echocardiography at 24 hr, 30 days, 90 days, 180 days, and 360 days after implantation. Residual shunt, left pulmonary artery (LPA) and descending aortic velocities were among the parameters assessed. All occluders were delivered via 6-8 F long sheaths and PDA closures were performed following standard techniques.

    RESULTS: Thirty three patients (20 female/13 male), with a median age of 2 years (6 month to 38 years), and median weight of 9.3 kg (6-69.2 kg) were included. The narrowest median PDA diameter was 3mm (1.8-5.8 mm). All the 33 patients were closed successfully using Occlutech ductal occluder, 16 patients (48.4%) had immediate and complete closure on angiography. Within 24 hr, color Doppler revealed complete closure in 27patients (81.8%), 32patients (97%) at 30 days, and in 100% of patients at 90 days. All patients with a large PDA had immediate residual shunt which was closed at the 90-day follow-up. There was no device embolization, hemolysis, or obstruction to the LPA or descending aorta.

    CONCLUSION: The new Occlutech® PDA is safe and effective. In patients with a large PDA complete closure tended to take longer time.

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