David W. Baron

Prognostic guides in patients with idiopathic or ischemic dilated cardiomyopathy assessed for cardiac transplantation

In an attempt to identify which parameters predict survival in advanced dilated cardiomyopathy, 232 patients presenting for assessment for cardiac transplantation were investigated and followed for 10 +/- 12 months (range 2 weeks to 5 years). Etiology of dilated cardiomyopathy included ischemic heart disease (33%), idiopathic (42%) and miscellaneous (25%). In each patient, 26 parameters were recorded. Whole group survival was 68% at 1 year, 56% at 2 years, 41% at 3 years and 25% at 4 years. On Cox multivariate regression analysis, 3 parameters predicted survival: New York Heart Association symptom class (p less than 0.0001), pulmonary capillary wedge pressure (p less than 0.008) and plasma atrial natriuretic factor level (p less than 0.002). On paired testing of actuarial survival curves, plasma noradrenaline also held predictive value (p less than 0.002), as did left ventricular ejection fraction less than or equal to 20% on radionuclide ventriculography (p = 0.007) and presence of greater than or equal to 4 beats of ventricular tachycardia on Holter monitoring (p = 0.007). Treatment with amiodarone did not appear to influence survival. Conventional determinants of prognosis in cardiomyopathy (symptom class, wedge pressure, nonsustained ventricular tachycardia and ejection fraction) do not alone always adequately differentiate survival in this group of high risk patients. More attention to plasma noradrenaline and to atrial natriuretic factor levels may give important additional information in the context of assessment of patients for transplantation.

Limitation of myocardial infarction by early infusion of recombinant tissue-type plasminogen activator.

In a double-blind randomized trial involving five Sydney hospitals and the city ambulance paramedical service, 145 patients with a first evolving myocardial infarction and with onset of pain less than 2.5 (mean 1.9 +/- 0.5 [SD]) hr previously were allocated to intravenous infusion of 100 mg recombinant tissue-type plasminogen activator (rt-PA) or placebo over 3 hr. The groups at entry were similar. At assessment 21 days later, left ventricular ejection fraction measured both by contrast and radionuclide ventriculography was higher in the rt-PA compared with the placebo group (61 +/- 13%, n = 64, vs 54 +/- 14%, n = 62, contrast, 2p = .006; 52 +/- 13%, n = 66, vs 48 +/- 13%, n = 62 isotope, 2p = .08). This indicates limitation of myocardial infarction by rt-PA.

Immediate postoperative aspirin improves vein graft patency early and late after coronary artery bypass graft surgery. A placebo-controlled, randomized study.

BackgroundThe efficacy of aspirin for prevention of thrombotic graft occlusion after coronary artery bypass grafting (CABG) depends both on the dosage and time window of administration. Early and late graft patency were therefore assessed in a prospective, double-blind, randomized, placebo-controlled trial of aspirin, 324 mg daily, given within 1 hour of CABG. Methods and ResultsAngiographic graft patency was determined at 1 week (231 patients) and year (219 patients) after CABG. The early vein graft occlusion rate was 1.6% on aspirin and 6.2% on placebo (p = 0.004), and late graft occlusion rate was 5.8% on continued aspirin and 11.6% on placebo (p = 0.01). New graft occlusion between 1 week and 1 year was less common in patients on aspirin than on placebo (4.3% versus 7.4%, p = 0.013). The protective effect of aspirin against occlusion persisted in most subgroups of graft type, graft flow, diameter of recipient artery, location of grafted artery, and endarterectomy. Mean chest tube blood loss for the first 24 hours was 571 ml for the aspirin group and 563 ml for the placebo group. Red cell transfusion requirements were 902 ml in the aspirin group and 934 ml in the placebo group (p=NS). The reoperation rate was 4.8% in the aspirin group and 1% in the placebo group (p = 0.1). ConclusionsImmediate postoperative administration of aspirin (324 mg) improves early graft patency and, with continued usage, protects against further occlusion up to 1 year after CABG. Postoperative blood loss was similar in the two groups; however, aspirin was associated with a nonsignificant higher rate of reoperation.

Contribution of left ventricular contraction to the generation of right ventricular systolic pressure in the human heart.

To determine whether left ventricular (LV) contraction contributes to the generation of right ventricular (RV) systolic pressure in humans, LV and RV pressures and their first derivative (dP/dt) were recorded simultaneously with micromanometer-tipped catheters in 11 conscious subjects. Seven subjects had normal LV and coronary angiograms. Four subjects had moderate LV dysfunction (resting ejection fraction 0.40 to 0.50), and three of these had coronary artery disease. During normal sinus rhythm, LV contraction slightly preceded RV contraction (mean 20 msec), and LV and RV dP/dt recordings showed single positive systolic peaks that were coincident. During endocardial pacing of the RV free wall, RV contraction preceded LV contraction (mean 23 msec) and two systolic RV dP/dt peaks were recorded, the first (peak I) occurring significantly before (mean +/- SD = 67 +/- 23 msec, p less than .01), and the second (peak II) coincident with the single systolic LV dP/dt peak. RV ectopic beats produced a similar RV dP/dt pattern, with peak I occurring 63 +/- 11 msec (p less than .01) before, and peak II coincident with the single LV dP/dt peak. Conversely, during LV ectopic beats, LV contraction preceded RV contraction (mean 63 msec) and two systolic RV dP/dt peaks were recorded, but peak I was coincident with the single LV dP/dt peak, while peak II occurred significantly later (63 +/- 26 msec, p less than .01). In two subjects right bundle branch block produced similar findings. In three subjects left bundle branch block produced little ventricular asynchrony (mean 14 msec), but did delay the development of peak LV dP/dt after LV contraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Timing of cardiac transplantation in idiopathic dilated cardiomyopathy

Seventy-nine patients with idiopathic dilated cardiomyopathy were assessed and followed up to evaluate 9 variables that might predict duration of survival after assessment for cardiac transplantation. Patients with ischemic heart disease, alcoholic and peripartum cardiomyopathy were excluded. There were 38 deaths (48%) during the 18-month (mean) follow-up. Patients underwent determination of left ventricular ejection fraction by radionuclide scan, echocardiography, cardiac catheterization and myocardial biopsy. Only left ventricular ejection fraction determined by radionuclide study correlated significantly with time to death in nonsurvivors (r = 0.38, p less than 0.05). Multivariant analysis and Cox multivariate regression analysis revealed that the single consistent determinant of prognosis was radionuclide-determined ejection fraction. It was an excellent predictor of survival to 3 months (p less than 0.0001) and a reasonable predictor of survival to 6 months (p less than 0.05). There was no variable that efficiently predicted survival for any period greater than 6 months. In 15 of 70 patients (21% of the entire group), clinical status and radionuclide ejection fraction improved after assessment but only one of these had an ejection fraction less than or equal to 0.10. No patient with a radionuclide ejection fraction greater than or equal to 0.20 died within 6 months of assessment. For those with ejection fraction between 0.11 and 0.19, survival after cardiac transplantation exceeded that of the natural history of their disease; this suggests that transplantation should be undertaken within 6 to 12 months of assessment. Left ventricular ejection fraction less than or equal to 0.10 predicts an extremely poor prognosis (6-month survival was 17%) and such patients should be transplanted with minimal delay.

Coronary artery stenting for spontaneous coronary artery dissection: A case report and review of the literature

Spontaneous coronary artery dissection is an uncommon cause of acute coronary syndromes. It occurs in three major groups: in young women in the peripartum period, in patients with atherosclerotic disease, and in an idiopathic group. There are a number of associated conditions, but the pathogenesis remains unclear. Diagnosis can only be made at angiography. Treatments include medical therapy, coronary artery bypass grafts, and newer interventional procedures. We report on a case of spontaneous coronary artery dissection involving the left circumflex artery in a young adult male presenting with a myocardial infarction after exercise. There were no risk factors for coronary artery disease and no evidence of atherosclerosis on angiography. The dissection was treated with primary coronary artery stenting without predilation, achieving an excellent result. To our knowledge, this is the third known case of successful coronary artery stenting for this condition and the first case of primary stenting without prior angioplasty.

Staged carotid artery stenting and coronary artery bypass graft surgery: Initial results from a single center

The objective of this study was to assess the clinical course of patients undergoing planned percutaneous carotid stenting followed by staged coronary artery bypass grafting (CABG). Coexisting carotid and coronary atherosclerotic disease is relatively common. A combined or staged surgical approach has a composite stroke, myocardial infarction, or death rate of > 10%. We performed a retrospective search of our single‐institution database to identify all patients scheduled to undergo staged carotid stenting followed by CABG. Twenty‐three such patients (17 males, 6 females) were identified, with 3/23 (13%) requiring bilateral carotid stenting. Most carotid lesions were asymptomatic (18/26; 69.2%) and severe (mean stenosis, 82.9% 6± 8.6%). Stents were successfully placed in 26/26 carotid arteries (100%). One stent procedure (1/26; 3.8%) resulted in a minor stroke, but full recovery occurred within 1 week. There were no other peristenting complications. Three patents (3/23; 13%), none of whom suffered an adverse event at carotid stenting, elected not to undergo CABG. The mean interval from last carotid stent to CABG was 69.6 6± 39.6 days (range, 8–157 days). Antiplatelet therapy was ceased > 3 days prior to CABG in 10/20 patients (50%), but continued until surgery in the remainder. There were no peri‐CABG bleeding or neurological complications, but one myocardial infarction occurred (1/20; 5%). Therefore, of the 20 patients who underwent planned carotid stenting followed by CABG, our overall rate of death, stroke, or myocardial infarction was 10%. However, our rate of death, persistent stroke or myocardial infarction was 5%. Planned carotid stenting followed by staged CABG is a viable method of treatment for patients with coexistent carotid and coronary atherosclerosis.© 2005 Wiley‐Liss, Inc.

Initial experience with the balloon expandable Edwards-SAPIEN Transcatheter Heart Valve in Australia and New Zealand: The SOURCE ANZ registry: Outcomes at 30 days and one year

BACKGROUND We report the findings of the SOURCE-ANZ registry of the clinical outcomes of the Edwards SAPIEN™ Transcatheter Heart Valve (THV) in the Australian and New Zealand (ANZ) clinical environment. METHODS This single arm registry of select patients treated in eight centres, represent the initial experience within ANZ with the balloon expandable Edwards SAPIEN THV delivered by transfemoral (TF) and transapical (TA) access. RESULTS The total enrolment for the study was 132 patients, 63 patients treated by TF, 56 by TA, and 2 patients were withdrawn from the study. The mean ages: 83.7 (TF) and 81.7 (TA), female: 34.3% (TF) and 61.3% (TA), logistic EuroSCORE: 26.8% (TF) and 28.8% (TA), and with procedural success (successful implant without conversion to surgery or death): 92.4% (TF) and 87.1% (TA) (p=0.32). Outcomes were not significantly different between TF and TA implants. These included one year mortality of 13.6% (TF) and 21.7% (TA) (p=0.24), MACCE: 16.7% (TF) and 28.3% (TA) (p=0.12), pacemaker: 4.6% (TF) and 8.3% (TA) (p=0.39), and VARC major vascular complication of 4.6% (TF) and 5.0% (TA) (p=0.91). CONCLUSION TAVI in the ANZ clinical environment has demonstrated excellent outcomes for both the TA and TF approaches in highly selected patients. These results are consistent with those demonstrated in European, Canadian registries and the pivotal US clinical trials. ACTRN12611001026910.

Torsades de Pointes in a Patient with Kearns-Sayre Syndrome: A Fortunate Finding

We present a case of a 33‐year‐old woman with Kearns‐Sayre syndrome (KSS) who had a pacemaker implanted for complete heart block postpartum and was found to have torsades de pointes. KSS is a rare encephalomyopathy associated with varying levels of central nervous system involvement, typically resulting in progressive external opthalmoplegia and retinal degeneration. Onset of cardiac conduction disease can be insidious and is a strong predictor of sudden cardiac death. The mainstay of treatment has been the judicious implantation of pacemakers. However, as highlighted in this case, patients who have an underlying cardiomyopathy may be more appropriately treated with an implantable cardioverter defibrillator.

Increased plasma beta-thromboglobulin in patients with coronary artery vein graft occlusion : response to low dose aspirin

The therapeutic effect of aspirin on vein graft patency was studied in patients undergoing coronary artery bypass graft surgery. The study design enabled the prospective evaluation of the relation of platelet activation, as measured by plasma beta-thromboglobulin concentration, to subsequent coronary vein graft occlusion. Serial beta-thromboglobulin levels were measured in 105 patients randomized to receive aspirin (324 mg/day) or placebo beginning within 1 h after surgery. Graft patency was assessed angiographically at 1 week and 1 year after surgery. Of 49 patients receiving placebo, 17 (34.7%) had one or more graft occlusions, 6 early, 10 late and 1 with both early and late occlusion. Of 56 patients receiving aspirin, 7 (12.5%) had one or more occlusions, 3 early and 4 late (p less than 0.01). Preoperatively, the beta-thromboglobulin level in surgical patients (29 +/- 13.5 ng/ml) was significantly higher than that of 51 control subjects (22.6 +/- 11.1 ng/ml) (p less than 0.004). Plasma beta-thromboglobulin levels remained comparatively constant at 3 and 12 months after surgery in the 43 patients who had both samples available (p less than 0.001, r = 0.65). The reduction in beta-thromboglobulin concentration from the preoperative level to 12 months postoperatively was greater in the aspirin-treated group (p less than 0.001). Multivariate logistic regression analysis demonstrated a significant association between preoperative beta-thromboglobulin concentration and graft occlusion (p less than 0.02), and aspirin treatment was effective in preventing occlusion when adjusted for the preoperative beta-thromboglobulin level (p less than 0.005). Plasma beta-thromboglobulin concentrations are elevated in patients with coronary artery disease, suggesting ongoing platelet activation.(ABSTRACT TRUNCATED AT 250 WORDS)