Douglas D. Payne

Cystic medial necrosis in coarctation of the aorta: a potential factor contributing to adverse consequences observed after percutaneous balloon angioplasty of coarctation sites.

Percutaneous transluminal angioplasty has been shown to be both feasible and efficacious for the treatment of aortic coarctation. Recent reports, however, have indicated that the development of aortic aneurysms at or near the coarctation segment may complicate attempts to treat this lesion by catheter-based intervention. Accordingly, we examined the light microscopic features of coarctation segments excised at surgery (n = 31) or obtained at autopsy (n = 2) in 33 patients with coarctation of the aorta. Cystic medial necrosis, defined as depletion and disarray of elastic tissue, was observed in each of the 33 specimens. In the majority of coarctation specimens (22 of 33 or 67%) the extent of cystic medial necrosis, graded semiquantitatively on a scale of 0 (normal aorta) to 3+, was severe (3+). The finding that cystic medial necrosis represents a consistent histologic feature of coarctation of the aorta provides a pathologic basis for the formation of aneurysms observed after balloon angioplasty of coarctation sites.

Expanding the indications for pulmonary valve replacement after repair of tetralogy of fallot

BACKGROUND Insertion of a competent pulmonary valve has been advocated to reduce right ventricular volume overload associated with pulmonary regurgitation (PR) after repair of tetralogy of Fallot. However the indications, proper timing, and long-term benefits of restoring pulmonary valve function remain controversial. METHODS Thirty-six patients (aged 15.2 +/- 9.2 years) underwent pulmonary valve implantation (31 homografts, 5 heterografts) 12.2 +/- 6.9 years after tetralogy repair. Additional surgical procedures included pulmonary artery augmentation (n = 14), closure of septal defects (n = 10), and cryoablation and endocardial resection of ventricular tachycardia (n = 2). RESULTS All patients have had clinical improvement in their exercise capacity. Preoperative and postoperative bicycle ergometry tests in 6 patients demonstrated significant improvement in the percent of predicted peak workload (68.5% +/- 19.8% to 80.7% +/- 17.4%, p < 0.015). One midterm death occurred in a 38-year-old patient with a history of ventricular tachycardia who died suddenly 2 years after pulmonary valve insertion. Postoperative echocardiographic measurements were available in 34 patients at a mean follow-up of 5 years. There was a 30% reduction in right ventricular end-diastolic diameter indexed to body surface area after surgery (30.1 +/- 10.2 to 18.6 +/- 6.0 mm/m(2), p < 0.0001). Two patients required conduit replacements at 1 and 9 years postoperatively. CONCLUSIONS Timely insertion of a competent pulmonary valve in children, adolescents, and young adults with significant PR after tetralogy of Fallot repair results in subjective and objective improvement in exercise capacity and is associated with reduction in right ventricle size.

Repair of coarctation of the aorta during infancy minimizes the risk of late hypertension.

BACKGROUND Recent surgical reports on coarctation of the aorta have primarily focused on the relative merits of various operative techniques. However, appropriate timing for elective repair remains unclear. METHODS In a retrospective analysis we examined the surgical outcomes in 176 consecutive patients undergoing repair of coarctation of the aorta in our institution over a 25-year period. Ninety-nine percent of the patients had follow-up for a median of 7.5 years. RESULTS A total of 13 patients have died (7.4% overall mortality). Nine of these patients had associated complex intracardiac anomalies. There was no mortality in the 113 patients with isolated coarctation. Residual or recurrent coarctation occurred in 27 patients (15.3%). The age at operation and the type of surgical repair did not have an effect on the incidence of recurrence. Persistent or late hypertension was identified in 18 of the 107 patients who have been followed up for more than 5 years (16.8%). A total of 48 patients operated on during infancy have been followed up for more than 5 years. Only 2 have developed late hypertension (4.2%). Both of these patients had recurrence. In contrast, 16 of the 59 patients operated on after a year of age had late hypertension (27.1%). CONCLUSIONS To minimize the risk of persistent hypertension, elective repair of coarctation should be performed within the first year of life.

Clinical benefits of endoscopic vein harvesting in patients with risk factors for saphenectomy wound infections undergoing coronary artery bypass grafting

OBJECTIVE The influence of endoscopic harvesting techniques on the prevalence of leg-wound complications after coronary artery bypass grafting remains to be defined for patients at high risk for the development of wound infections. METHODS Among 1473 patients undergoing coronary artery bypass grafting who had the saphenous vein harvested by either a continuous incision or skip incisions leaving intact skin bridges, we determined the prevalence of wound infections to be 9.6%. The following variables were entered into logistic regression analysis to identify significant risk factors that might be predictive of wound infection: diabetes, peripheral vascular disease, obesity, renal failure, steroid use, age, sex, and type of closure. We then prospectively randomized 132 patients found to be at high risk of wound infection to either endoscopic vein harvesting or a continuous open incision. RESULTS Univariate analysis showed female sex (P =.04), diabetes (P <.001), and obesity (P <.001) to be predictors of wound infection. In a multivariate model diabetes (P =.02) and obesity (P =.001) were independent predictors. In patients at high risk, the prevalence of wound infection was 4.5% for the endoscopic group versus 20% for the open group (P =.01). Vein procurement time was greater in the endoscopic group (65 minutes vs 32 minutes, P <.001), as was the number of vein repairs required (2.5 vs 0.6, P <.001). CONCLUSION The use of endoscopic vein harvesting decreases the prevalence of postoperative leg-wound infections in high-risk patients with diabetes and obesity. Whether this translates into an economic benefit that justifies the additional cost of that technology requires further analysis.

Carotid occlusive disease and stroke risk in coronary artery bypass graft surgery

To clarify the perioperative stroke risk in patients with carotid stenosis or occlusion having coronary artery bypass graft (CABG) surgery, we retrospectively reviewed the records of 1,022 patients who had CABG during a 2-year period (1992, 1993). Of these, 224 had preoperative carotid duplex studies, usually for bruit or remote symptoms. We analyzed clinical and neuroimaging findings for all patients who had strokes to determine infarct topography and presumed mechanism, either low perfusion or embolism. Perioperative stroke was always ipsilateral to severe (≥70%) carotid disease, and occurred in 2 (8.0%) of 25 patients with carotid occlusion, 3(50.0%) of 6 patients with 70 to 99% stenosis, and 9 (4.7%) of 193 patients with less than 70% stenosis. Borderzone infarcts occurred with all degrees of carotid stenosis. Stroke frequency had a positive correlation with the degree of carotid stenosis. Eight (1.0%) of the 798 patients not studied by carotid duplex had stroke in various vascular distributions. Overall, stroke occurred in 22 (2.2%) of the 1,022 patients having CABG surgery. Our results suggest that while the overall risk of perioperative stroke in CABG surgery is low, the risk is increased in patients with severe extracranial carotid stenosis or occlusion. The role of carotid disease and the mechanism of borderzone infarction in CABG surgery remain unsettled.

The impact of coronary artery disease on carotid endarterectomy.

In a series of 531 CENDX, preoperative cardiac risk was categorized by clinical criteria. Patients with CAD (history of previous MI, angina, congestive heart failure, and/or electrocardiographic evidence of CAD were selected for more invasive studies based on clinical criteria. The overall incidence of postoperative myocardial infarction was 2.5% and increased slightly to 4% in patients with symptomatic cardiac disease. More importantly, the overall mortality was 0.9% and only 3 of 13 (23%) postoperative myocardial infarctions were fatal. Neurologic complications averaged 1.4% and approximately 70% were related to preceding cardiac events. Twenty-two patients or 4% of the entire series underwent carotid endarterectomy combined with coronary artery bypass graft and this approach was associated with one death and one stroke. Therefore, we conclude that a selective approach to coronary arteriography and subsequent CABG based on clinical criteria is associated with an acceptably low mortality and cardiac morbidity.

Efficacy of Retrograde Coronary Sinus Cardioplegia in Patients Undergoing Myocardial Revascularization: A Prospective Randomized Trial

The efficacy of retrograde coronary sinus cardioplegia (RCSC) administered through the right atrium compared with aortic root cardioplegia (ARC) has not been examined critically in patients undergoing coronary artery bypass grafting (CABG). Twenty patients having elective CABG were randomized prospectively to receive cold blood ARC (Group I, 10 patients) or cold blood RCSC (Group II, 10 patients). Patient demographics were similar in both groups. Ventricular function was assessed preoperatively by radionuclide ventriculography and postoperatively by simultaneous hemodynamic and radionuclide ventriculographic studies with volume loading. There was no change in ejection fraction (EF) (preoperative versus postoperative value) in Group I (50 +/- 6% versus 53 +/- 6%) but in group II, at similar peak systolic pressure and similar left ventricular end-diastolic volume index (LVEDVI), LVEF improved significantly (49 +/- 6% versus 60 +/- 12%, p less than 0.05). Postoperative ventricular function (stroke work index versus EDVI) for the left ventricle and right ventricle were similar in both groups. Evaluation of postoperative LV systolic function (end-systolic blood pressure versus end-systolic volume index) and diastolic function (pulmonary capillary wedge pressure versus EDVI) were also similar in both groups. Retrograde coronary sinus cardioplegia is as effective as ARC for intraoperative myocardial protection, and provides excellent postoperative function in patients undergoing elective CABG.

Application of gene network analysis techniques identifies AXIN1/PDIA2 and endoglin haplotypes associated with bicuspid aortic valve.

Bicuspid Aortic Valve (BAV) is a highly heritable congenital heart defect. The low frequency of BAV (1% of general population) limits our ability to perform genome-wide association studies. We present the application of four a priori SNP selection techniques, reducing the multiple-testing penalty by restricting analysis to SNPs relevant to BAV in a genome-wide SNP dataset from a cohort of 68 BAV probands and 830 control subjects. Two knowledge-based approaches, CANDID and STRING, were used to systematically identify BAV genes, and their SNPs, from the published literature, microarray expression studies and a genome scan. We additionally tested Functionally Interpolating SNPs (fitSNPs) present on the array; the fourth consisted of SNPs selected by Random Forests, a machine learning approach. These approaches reduced the multiple testing penalty by lowering the fraction of the genome probed to 0.19% of the total, while increasing the likelihood of studying SNPs within relevant BAV genes and pathways. Three loci were identified by CANDID, STRING, and fitSNPS. A haplotype within the AXIN1-PDIA2 locus (p-value of 2.926×10−06) and a haplotype within the Endoglin gene (p-value of 5.881×10−04) were found to be strongly associated with BAV. The Random Forests approach identified a SNP on chromosome 3 in association with BAV (p-value 5.061×10−06). The results presented here support an important role for genetic variants in BAV and provide support for additional studies in well-powered cohorts. Further, these studies demonstrate that leveraging existing expression and genomic data in the context of GWAS studies can identify biologically relevant genes and pathways associated with a congenital heart defect.

Laser myoplasty for hypertrophic cardiomyopathy. In vitro experience in human postmortem hearts and in vivo experience in a canine model (transarterial) and human patient (intraoperative).

The feasibility of performing a myotomy/myectomy for hypertrophic cardiomyopathy (HC) by means of laser phototherapy was evaluated experimentally in vitro and in vivo, and the procedure then applied to a patient intraoperatively. In vitro experience revealed that the beam of an argon laser, delivered directly or via an optical fiber, could both cut and vaporize myocardium, producing a myotomy/myectomy morphologically similar to that produced by the conventional blade technique. In vivo experiments, in which the beam of an argon laser was delivered via an optical fiber to the ventricular septum of a canine heart, confirmed that a laser myoplasty could be achieved in 4 of 5 dogs by a transarterial approach. Finally, laser myoplasty was performed intraoperatively in a patient with HC, using a 200-mu fiber interfaced with an argon laser. Measured laser power was 1.5 W; cumulative exposure was less than 4 minutes; the myoplasty was 4 X 1 X 0.5 cm. These investigations establish the feasibility of using laser therapy to create a myoplasty trough that is similar in appearance to that typically achieved by the conventional blade technique. Illumination of the intraventricular operative field and precise modeling of the myoplasty trough constitute the principal advantages of laser myoplasty for HC.

Surgical therapy for drug-refractory ventricular tachycardia: Results with mapping-guided subendocardial resection

Surgical therapy with mapping-guided subendocardial resection was used in 30 patients with drug-refractory ventricular tachycardia. Results of preoperative, intraoperative and postoperative electrophysiologic evaluation and long-term clinical follow-up are reported. Left ventricular aneurysm was located in the inferior wall in 8 patients and in the anterior wall in 22. Left ventricular mapping was performed in 15 patients preoperatively and in all 30 patients intraoperatively. Subendocardial resection was supplemented with cryoablation in 26 patients and with laser photocoagulation in 4. Coronary bypass surgery was performed in 27 patients. The surgical mortality rate was 10%; the three deaths were due to cardiogenic shock, pneumonia and sepsis, respectively. At postoperative electrophysiologic study, ventricular tachycardia was inducible in 8 (30%) of 27 patients. Previously ineffective antiarrhythmic drugs were effective in preventing the induction of ventricular tachycardia in four of these eight patients. Two of the remaining four patients received an automatic implantable cardioverterdefibrillator; the other two were treated with amiodarone. At a mean follow-up period of 18 +/- 17 months (range 1 to 52), there has been one sudden death and one nonfatal recurrence of ventricular tachycardia in the 18 patients without inducible arrhythmias postoperatively. Among the eight patients with inducible ventricular tachycardia after subendocardial resection, there has been one nonfatal ventricular tachycardia recurrence. Thus, among the 27 patients surviving surgery, 17 (63%) were cured with surgery alone, and another 7 (26%) had their ventricular tachycardia controlled with drugs (n = 5) or the defibrillator (n = 2). Inability to completely map the tachycardia, a clinical history of cardiac arrest requiring resuscitation and the presence of myocardial infarction within 2 months predicted postoperative arrhythmia inducibility and recurrence.