Iraj A. Kashani

Atrial septostomy as a bridge to lung transplantation in patients with severe pulmonary hypertension

Long waiting times for lung transplantation have limited the survival of patients with advanced pulmonary hypertension. Atrial septostomy has been used in this group of patients in an attempt to prolong survival. We evaluated the results of atrial septostomy in 12 patients using the static graded balloon dilation technique. Between December 1990 and May 1998, 10 women and 2 men (ages 13 to 56 years, mean 37 years) underwent atrial septostomy. Nine patients had primary and 3 patents had secondary pulmonary hypertension. Five patients deteriorated despite long-term intravenous prostacyclin infusions. The atrial septum was crossed with a Brockenbrough needle, followed by an 0.035-J exchange wire and progressively larger catheter balloons for atrial septal dilation, until systemic oxygen saturation decreased 5% to 10%. An atrial septal defect was successfully created in each patient. The mean right atrial pressure decreased from 23 to 18 mm Hg and the mean systemic oxygen saturation decreased from 93% to 85%. The mean cardiac index increased from 1.7 to 2.1 L/min/m2 and the mean systemic oxygen transport increased from 268 to 317 ml/min/m2. Complications occurred in 3 patients: transient hypotension during transesophageal echocardiography, a femoral pseudoaneurysm, and a femoral arteriovenous fistula. After septostomy, 6 patients had clinical improvement (resolution of ascites, edema, and no further episodes of syncope); 5 of these 6 patients underwent lung transplantation a mean of 6.1 months after septostomy. Six patients did not have clinical improvement after septostomy. Atrial septostomy improves the hemodynamic status and may be useful as a bridge to lung transplantation in selected patients with pulmonary hypertension.

Percutaneous coil occlusion of patent ductus arteriosus

OBJECTIVE To determine the success rate and safety of percutaneous patient ductus arteriosus (PDA) coll occlusion. DESIGN Thirty consecutive pediatric patients with small to moderate-size PDAs (minimum diameter < or = 4 mm) underwent percutaneous coll occlusion. The results were assessed by angiography and echocardiography. The mean age was 5.1 +/- 4.2 years (range, 0.8 to 18.8 years); mean weight was 19.2 +/- 10.3 kg (range, 8.1 to 40.0 kg). The mean minimum diameter of the PDA was 1.8 +/- 0.8 mm (range, 1.0 to 4.0 mm). RESULTS PDA occlusion was achieved with one coil in 24 patients, 2 coils in 3 patients and 3 coils in 3 patients. The mean coil/PDA diameter ratio was 2.5 +/- 0.5. Immediately after coil occlusion, 29 PDAs had no flow by anglography; one had a small residual shunt. There were no significant complications. In the first 24 hours after coil implantation, echocardiography showed complete occlusion in 28 patients, a small left-to-right shunt in the same patient that had a residual shunt by anglography, and a trace shunt in one additional patient. In the two patients with residual flow by echocardiography, follow-up ultrasonography revealed no residual shunt 1 and 3 months later. At a mean follow-up of 11.8 +/- 9.3 months (range, 0 to 36.0 months), there was no PDA flow by color Doppler echocardiography in any of the 30 patients. CONCLUSION Coil occlusion is a safe and effective method of percutaneous closure of small to moderate-size PDAs. The largest PDA that can be closed with this technique remains to be determined.

Balloon angioplasty of native aortic coarctation in infants 3 months of age and younger.

The use of balloon dilation to treat native aortic coarctation is controversial, particularly in infants. Between January 1991 and September 1996, 12 patients < or = 3 months of age with native coarctation of the aorta (CoA) underwent balloon angioplasty (BA). All 12 lesions were dilated successfully with a mean reduction in peak systolic gradient from 49.3 +/- 16.5 mm Hg to 6.8 +/- 4.0 mm Hg (p < 0.001) and a mean increase in minimum CoA diameter from 2.4 +/- 0.6 mm to 5.5 +/- 1.3 mm (p < 0.001). Intimal flaps or tears were detected immediately after BA in 4 (33%) of 12 patients by angiography and in 8 (89%) of 9 patients by intravascular ultrasonography. No deaths or major complications related to the BA occurred. One patient had documented asymptomatic femoral artery obstruction, and one patient with hydrops fetalis and congenital pleural effusions died with gram-negative sepsis 1 week after the procedure. Follow-up was available for 10 patients (1 was lost to follow-up) between 2 months and 4.1 years (mean 2.4 +/- 1.3 years) after BA. No patient had an aortic aneurysm. Restenosis occurred in 5 (50%) of 10 patients, requiring reintervention a mean of 2.6 +/- 2.1 months after BA. One patient underwent surgical repair. Repeat BAs were performed in the other four patients; three were successful, and one with partial gradient relief required surgical repair. Five patients have not required reintervention a mean of 2.9 +/- 1.0 years after the initial BA. Among these five patients, follow-up intravascular ultrasound performed in three patients a mean of 2.0 +/- 1.9 years after BA showed favorable endovascular remodeling. There was a tendency for early reintervention in patients < 1 month of age and coexistence of a patent ductus arteriosus at the time of BA. In conclusion, selected infants < or = 3 months of age with discrete native CoA may be treated initially with balloon dilation. Most patients who have restenosis respond successfully to repeat BA.

Successful balloon dilation of an abdominal coarctation of the aorta in a patient with presumed Takayasu's aortitis

An 11-year-old male with a severe abdominal aortic coarctation, presumably secondary to aortitis, underwent successful percutaneous balloon dilation that resulted in near-complete relief of the obstruction. Intravascular ultrasound imaging showed a major endovascular tear immediately following dilation and satisfactorily excluded significant branch (superior mesenteric) artery compromise. Arterial remodeling was demonstrated with persistence of the gradient relief over a 12-month follow-up period.

Familial occurrence of pulmonary atresia with intact ventricular septum

Pulmonary atresia with intact ventricular septum (PA/IVS) is a rare disease, accounting for less than 3% of all congenital heart lesions. The cause of PA/IVS is unknown. We report the occurrence of two first cousins with PA/IVS, suggestive of autosomal dominant inheritance with incomplete penetrance. The study of such families should ultimately lead to the identification of the gene(s) that cause congenital heart disease.

Reptilian Echocardiography: Insights into Ontogeny and Phylogeny?

We describe the echocardiographic findings in a large reptile‐the carpet python. If ontogeny recapitulates phylogeny, the study of reptilian hearts may provide insights into human cardiac development. In addition, the reptilian heart has unique structural and physiological adaptations that may broaden our perspective on evolutionary cardiac adaptation.

A randomized trial of cardiovascular risk factor reduction: patterns of attrition after randomization and during follow-up.

Background The Preventive Cardiology Center compared two intensities of behavior modification for cardiovascular disease (CVD) risk factors in persons at risk and their families. Characteristics of drop-outs both before and after intervention were compared with subjects who completed the 6-month trial. Methods A total of 333 individuals of all ages were enrolled in the study and randomly assigned by family to a single-session (‘skills’ group — low-intensity) or a five-session (‘practice’ group — high intensity) intervention. Baseline and follow-up assessments included a personal and family health questionnaire, nutritional intake survey, and clinic visit to obtain blood pressure, lipids, and height and weight data. Results Two hundred and forty adults over 18 years of age were randomly assigned to one of the two intervention groups, Of these, 68 subjects (28.3%) did not participate in the intervention. Multivariate analysis revealed that these ‘early drop-outs’ were significantly more likely to be non-white and to have had a lower LDL cholesterol. Of the 172 subjects attending the intervention, 70 (40.7%) did not attend the 6-month follow-up (‘late drop-outs’), Multivariate analysis revealed that, compared with follow-up attendees, non-attendees were significantly more likely to be white and to be current smokers. Conclusions Both early and late drop-outs in a randomized trial of CVD risk reduction were significantly different than continuing participants in several key factors. These differences suggest the use of caution in both interpreting and making generalizations about behavioral trials of risk factor reduction when attrition is high.

Electrophysiologic Effects of Verapamil in Children

The electrophysiologic effects of verapamil, a slow channel blocker, were investigated during diagnostic cardiac catheterization in 24 children premedicated with lytic cocktail. The ages ranged from 50 days to 12 years. Twenty had congenital and 4 had rheumatic heart disease. Surface EKG, high intra-atrial and His bundle electrograms were obtained in all before and 5 min after a single dose of verapamil (0.15 mg/Kg, max 5 mg iv). In 14 cases complete electropysiologic studies were performed using the atrial pacing and extrastimulus technique. Due to variability of the resting heart rates and the effect of cycle length on refractory periods each paced with identical S1-S1 interval before and after verapamil, thus allowing each case to serve as his own control. Verapamil prolonged the corrected AH interval in all (mean +/- SD; from 116 +/- 37 to 152 +/- 41 msec, p less than 0.01) and shortened the HV interval in 15/24 (mean +/- SD: from 55 +/- 13 to 47 +/- 9.9 msec, p less than 0.05). The effective and functional refractory periods of the total conduction system, the AV node (ERPAVN) and atrium (ERPA) increased significantly in 10/14. The most profound effect was on ERPAVN and ERPA (25.54 +/- 29 and 19.27 +/- 21.81 percent mean percent increase +/- SD respectively, p less than 0.01 and p less than 0.02). Our findings show that verapamil prolongs the effective and functional refractory periods of the cardiac conduction system with maximal effects on the AV node, thus suggesting the mechanism of its effectiveness in the treatment of reentrant supraventricular arrhythmias.

Comparison of results of stent implantation in small (<20 kg) children versus larger children with pulmonary artery stenoses

We compared the results of stent implantation for pulmonary artery stenoses in patients weighing <20 kg (group 1, 17 patients, 21 stents) versus those weighing > or = 20 kg (group 2, 11 patients, 13 stents). There was no significant difference in the mean percent increase in diameter or mean percent gradient reduction acutely and at short-term follow-up between group 1 and 2 patients.

Wire-snare technique with distal flow control for coil occlusion of a modified Blalock-Taussig shunt.

Coil occlusion of Blalock‐Taussig shunts has been associated with a high rate of device embolization. We describe a technique consisting of transvenous snaring and exteriorization of a guidewire advanced through a modified left Blalock‐Taussig shunt, allowing distal shunt flow control and successful coil occlusion of the shunt. Cathet. Cardiovasc. Intervent. 49:51–54, 2000.