Pericardial Access Through the Right Atrium in a Porcine Model

As procedures such as epicardial ventricular ablation and left atrial appendage occlusion become more commonplace, the need grows for safer techniques to access the physiologic pericardial space. Because this space contains minimal fluid for lubrication, prevailing methods of pericardial access pose considerable periprocedural risk to cardiac structures. Therefore, we devised a novel method of pericardial access in which carbon dioxide (CO₂) is insufflated through a right atrial puncture under fluoroscopic guidance, enabling clear visualization of the cardiac silhouette separating from the chest wall. We performed the procedure in 8 Landrace pigs, after which transthoracic percutaneous pericardial access was obtained by conventional means. All of the animals remained hemodynamically stable during the procedure, and none showed evidence of epicardial or coronary injury. The protective layer of CO₂ in the pericardial space anterior to the heart facilitated percutaneous access in our porcine model, and the absence of complications supports the potential safety of this method.     

Serum lipid levels in angiographically defined coronary artery disease.

To evaluate the association between serum cholesterol and triglyceride levels and angiographically determined coronary artery disease, two selected groups of 100 patients each were compared. The coronary artery disease group had significantly higher serum levels of both cholesterol and triglyceride. However, several types of analyses based on the quartile distribution of serum levels of cholesterol and triglyceride showed that the serum cholesterol level was more significantly associated with coronary artery disease than was the triglyceride level. This was especially true in relation to multivessel disease, the most severe form of coronary artery disease, and most marked in men. Association with coronary artery disease appeared to be continuous, rather than being related to any critical serum level, thus re-emphasizing the need to distinguish between desirable and average levels of serum cholesterol in countries with a high dietary intake of saturated fat.     

A-HeFT: old dog, new endothelial tricks

In conclusion, reduced nitric oxide bioactivity contributes to cardiac and vascular remodeling. Nitricoxide-enhancing therapy can slow cardiac andvascular remodeling. African-Americans with heart failure exhibit nitric oxide deficiency and a dramatic benefit from nitric-oxide-enhancing therapy. The potential benefit of this therapy in other groups with heart failure and in other vascular remodeling disease processes requires further study.     

A multicenter, randomized, double-blind, placebo-controlled trial of pimobendan, a new cardiotonic and vasodilator agent, in patients with severe congestive heart failure.

Pimobendan, a new oral cardiotonic and vasodilator agent, increases myocardial contractile force through specific inhibition of phosphodiesterase type III and increased calcium sensitivity of the myocardial contractile elements. The effects of pimobendan on left ventricular performance and maximal exercise capacity were studied in a multicenter, randomized, double-blind, placebo-controlled trial involving 52 patients with severe congestive heart failure despite diuretics, digoxin, and angiotensin-converting enzyme inhibitors. The acute hemodynamic evaluation included three single doses of 2.5, 5.0, and 10.0 mg of oral pimobendan, which was subsequently administered at a daily dose of 5 or 10 mg for 4 weeks. Acute administration of pimobendan significantly increased the resting cardiac index and lowered pulmonary capillary wedge pressure in a dose-dependent manner, whereas heart rate and systemic arterial pressure were not substantially altered. Patients receiving pimobendan, 5 and 10 mg daily, had a significantly greater increase in maximal exercise duration than those receiving placebo, that is, 144 +/- 30 and 124 +/- 33 seconds versus 58 +/- 25 seconds (p = 0.05). Peak oxygen uptake increased by 1.7 +/- 0.8 and 2.2 +/- 1.3 ml/kg/min in patients receiving pimobendan at a daily dose of 5 and 10 mg, respectively, whereas it decreased by 0.1 +/- 0.6 ml/kg/min in patients receiving placebo (p = 0.06). Thus pimobendan acutely improves resting left ventricular performance and chronically increases exercise duration and peak oxygen uptake in patients with severe congestive heart failure concomitantly treated with digoxin, diuretics, and angiotensin-converting enzyme inhibitors.     

The preferred approach for mitral valve surgery after CABG: right thoracotomy, hypothermia and avoidance of LIMA-LAD graft

BACKGROUND AND AIM OF THE STUDY: An alternative to avoid redo sternotomy in patients with patent left internal mammary artery-left anterior descending coronary artery (LIMA-LAD) grafts undergoing mitral valve surgery is right thoracotomy with moderate-deep hypothermia (approximately 20 degrees C) and fibrillatory arrest without aortic cross-clamping. Few reports exist which directly compare re-sternotomy and right thoracotomy. METHODS: Between July 1992 and February 2000, 47 patients (39 males, eight females; median age 66 years; range: 41-83 years; 41 in NYHA class III or IV) with patent LIMA-LAD grafts underwent mitral valve surgery. Thirty-seven patients were approached through a right thoracotomy with moderate-deep hypothermia (median 20 degrees C) and fibrillatory arrest (right thoracotomy group), and 10 were approached through a re-sternotomy, with aortic cross-clamping and cardioplegic arrest. The median ejection fraction was 42% (range: 20-71%). Univariate analysis was used to determine predictors of outcome, as well as to evaluate differences in characteristics between groups. RESULTS: Operative mortality (OM) and perioperative myocardial infarction for the entire cohort was 11% and 10%, respectively, and there were no inter-group differences. No preoperative characteristics were associated with OM. Two LIMA-LAD graft injuries occurred in the re-sternotomy group compared with none in the right thoracotomy group (20% versus 0%, p = 0.04). Transfusion requirements were also greater in the redo sternotomy group (median 7 versus 2 packed red blood cell units, p = 0.04). CONCLUSION: Right thoracotomy with moderate-deep hypothermia and fibrillatory arrest is the preferred approach for reoperative mitral valve surgery after coronary artery bypass grafting in the presence of patent LIMA-LAD grafts. These data suggest that this approach is associated with decreased incidence of LIMA-LAD graft injury, as well as reduced transfusion requirements.     

Doppler echocardiographic comparison of the Carpentier and Duran anuloplasty rings versus no ring after mitral valve repair for mitral regurgitation

To compare the hemodynamic results of different anuloplasty techniques of primary valve repair for mitral regurgitation, 122 patients were prospectively studied with Doppler echocardiograms 5 to 10 days after operation. Seventy-seven patients had mitral valve prolapse, 27 had coronary artery disease, 13 patients had rheumatic mitral valve lesions and 5 patients had infective endocarditis. Forty-eight patients received the flexible Duran ring, 46 received the more rigid Carpentier ring and 28 patients received no ring. Doppler echocardiography demonstrated a significant decrease in mitral valve area estimated by the pressure half-time method in patients who received either a Carpentier (2.6 +/- 0.8 cm2) or Duran ring (2.8 +/- 0.8 cm2) when compared with patients who received no ring (3.2 +/- 0.7 cm2) (p = 0.01). No significant differences were observed for peak transmitral diastolic velocity, peak transmitral diastolic gradient, or the grade of mitral regurgitation by color flow Doppler mapping between patients with and without rings. The etiology of mitral disease and concomitant surgical procedures accompanying mitral valve repair did not significantly influence mitral valve area, peak velocity or peak gradient. These data suggest that Carpentier and Duran rings decrease the hemodynamic mitral valve area; however, the decrease in valve area is small and not associated with a clinically important increase in transvalvular gradient.     

A 62-dose, 6-month therapy for pulmonary and extrapulmonary tuberculosis. A twice-weekly, directly observed, and cost-effective regimen

STUDY OBJECTIVE: To evaluate the efficacy and toxicity of a 62-dose, four-drug, 6-month, and directly observed regimen for treatment of pulmonary and extrapulmonary tuberculosis. DESIGN: An open, nonblinded clinical trial, with intended follow-up of patients for 36 months after the completion of therapy. SETTING: A metropolitan tuberculosis clinic in a public health department. PATIENTS: From March 1981 through April 1989, we enrolled 160 patients with suspected or known tuberculosis; 35 of these patients were excluded from the analysis. INTERVENTIONS: Isoniazid, rifampin, pyrazinamide, and streptomycin were administered daily for 2 weeks; these drugs were then given in higher doses twice weekly for 6 weeks, followed by isoniazid and rifampin twice weekly for 6 weeks, followed by isoniazid and rifampin twice weekly for 18 weeks. A total of 62 doses were administered, and all therapy was directly observed by a nurse or an outreach worker. MEASUREMENTS AND MAIN RESULTS: Of the 125 evaluable patients, 101 (81%) had pulmonary tuberculosis, 7 (6%) had both pulmonary and extrapulmonary involvement, and 17 (13%) had extrapulmonary disease only. Seventy-one (57%) patients had a history of recent alcoholism. There were two relapses (1.6% +/- 2.2%), occurring 6 and 56 months after the completion of therapy. The time at which sputum samples became culture negative in pulmonary patients ranged from 1 to 19 weeks (median, 4.6 weeks); 40% +/- 9.6% of patients were culture-negative after 4 weeks of therapy, 75% +/- 8.5% after 8 weeks, 94% +/- 4.7% after 12 weeks, 97% +/- 3.3% after 16 weeks, and 100% after 20 weeks. Adverse drug reactions included hyperuricemia (greater than 178 mumol/L [3 mg/dL] above normal) secondary to pyrazinamide in 80 patients (64%), twofold or greater elevations of aspartate aminotransferase in 21 patients (17%), 1.5-fold or greater elevations of alkaline phosphatase in 33 patients (27%), cutaneous abnormalities in 8 patients (6%), nausea in five patients (4%), and dizziness in 1 patient (1%). CONCLUSIONS: This 62-dose, largely twice-weekly tuberculosis treatment regimen is efficacious and relatively nontoxic and is especially useful for patients in whom directly observed therapy is indicated.