Tirone E. David

Mitral valve annuloplasty: The effect of the type on left ventricular function

This study was undertaken to determine whether rigid-ring annuloplasty and flexible-ring annuloplasty have the same effect on left ventricular function in patients with chronic mitral regurgitation secondary to degenerative disease of the mitral valve. Twenty-five patients who underwent isolated mitral valve repair and required annuloplasty were randomized into two groups: rigid-ring and flexible-ring annuloplasty. Left ventricular function was assessed by echocardiography and radionuclide angiography on the day before operation and 2 to 3 months later. Preoperative left ventricular function was similar in the two groups of patients. Postoperatively, left ventricular end-diastolic diameter and volume decreased significantly in both groups. The left ventricular end-systolic diameter and volume decreased significantly only in patients with a flexible annuloplasty ring. Left ventricular systolic function as assessed by pressure-volume relationships was significantly better in patients with a flexible ring (p less than 0.02 by analysis of covariance), and left ventricular performance measured by stroke volume-end-diastolic volume relationships was also better in these patients (p less than 0.05 by analysis of covariance). These data indicate that patients with a flexible annuloplasty ring have better left ventricular systolic function than patients with a rigid annuloplasty ring 2 to 3 months after mitral valve reconstruction for chronic mitral regurgitation secondary to degenerative disease of the mitral valve.

Calcium Channel Blockade Does Not Offer Adequate Protection from Perioperative Myocardial Ischemia

This study aimed to detect the difference in hemodynamic and electrocardiographic responses during the prebypass period in patients undergoing coronary bypass grafting who were receiving beta-adrenergic blocking drugs, calcium entry blocking drugs, or both beta-adrenergic and calcium entry blocking drugs. Electrocardiographic evidence of myocardial ischemia was noted significantly more frequently in patients receiving calcium entry blocking drugs alone at induction of anesthesia (P < 0.03), skin incision (P < 0.05), and sternotomy (P < 0.002). Heart rate at sternotomy was significantly higher in patients receiving calcium entry blocking drugs (P < 0.02) as compared to patients receiving beta-adrenergic blocking drugs or the combination of both drugs. In conclusion, patients treated with calcium entry blocking drugs alone had significantly higher incidence of perioperative ischemic ECG changes compared with patients receiving beta-adrenergic blocking drugs alone or in combination with calcium channel blocking drugs.

Aortic valve replacement in adult patients with small aortic annuli.

Fifty-five patients with small aortic annuli underwent valve replacement either isolated or combined with other procedures. Patch enlargement of the aortic annulus in the area of the noncoronary sinus was used in 32 patients. The width of the patch was calculated by multiplying the desired increase in diameter by pi and adding 8 mm for suturing. The remaining 23 patients had aortic valve replacement with a prosthesis larger than the aortic annulus. The prosthesis was sutured in a supraannular position in the area corresponding to the noncoronary sinus. This slightly tilted position does not compromise function of Carpentier-Edwards or Björk-Shiley prostheses. Prosthetic gradients ranged from 0 to 18 mm Hg (9.2 +/- 3.9 mm Hg) in patients with patch enlargement of the aortic annulus and from 0 to 22 mm Hg (7.2 +/- 5.8 mm Hg) in patients with supraannular aortic prostheses. Although these techniques allow for insertion of prosthetic valves only one and two sizes larger than the aortic annulus, they appear to be satisfactory in most adult patients with a small aortic annulus.

EXCESSIVE REQUIREMENT FOR HEPARIN DURING CARDIAC SURGERY

A case of excessive heparin requirement during cardiopulmonary bypass is reported. A patient with sepsis secondary to a myocardial abscess required 13.5 mg . kg-1of heparin to increase his activated coagulation time to a therapeutic level. This phenomenon might be due to individual variability, lupus vasculitis, septicaemia, repeated thromboembolic phenomenon with hypercoagulable state, or chronic disseminated intravascular coagulation with partial antithrombin deficiency.RésuméLes auteurs rapportent le cas d’un malade ayant requis des doses très importantes d’héparine pour atteindre des niveaux thérapeutiques au cours d’une circulation extracorporelle. Ce patient hospitalisé en septicémie avec un abcès myocardique a subi une resection d’anévrysme ventriculaire avec résection de thrombi ventriculaires. On a dû administrer une dose totale d’héparine de 13.5 mk . kg-1 pour atteindre une héparinisation adéquate pour la circulation extra-corporelle.On a retenu plusieurs facteurs pouvant expliquer le phénomène dans ce cas particulier à savoir: la possibilité d’une variation individuelle de la sensibilité à l’héparine, la présence d’une vasculite à lupus, l’état de septicémie du malade, les épisodes emboliques répétés (avec un état d’hypercoagulabilité) survenus chez ce patient ou, enfin une coagulation intravasculaire chronique avec activité antithrombique déficiente.

Thromboembolism in Patients with Aortic Porcine Bioprostheses

Thromboembolism was prospectively studied in 215 patients who survived aortic valve replacement with porcine bioprostheses. All patients were anticoagulated with warfarin sodium during the first 3 postoperative months. Thereafter, 80 patients received aspirin (325 or 650 mg per day) and 135 received no antiplatelet or anticoagulant drugs. The two groups of patients were similar. Thromboembolic complications were carefully searched for during the follow-up interviews. Patients were removed from the study after a thromboembolic event unless there was no change in their management. The follow-up ranged from 6 to 80 months (mean, 36 months). The linearized thromboembolic rate in patients on a regimen of aspirin was 1.3% per patient-year and in patients not taking aspirin, 5.2% per patient-year (p less than 0.02). Replacement of the ascending aorta and patch enlargement of the aortic annulus with a Teflon graft were identified as significant risk factors for thromboembolism in patients with aortic porcine bioprostheses. These findings indicate that patients with aortic porcine bioprostheses should receive aspirin, especially if they also had replacement of the ascending aorta or patch enlargement of the aortic annulus with a Teflon graft.

Surgical Procedures Involving Cardiopulmonary Bypass in Patients Aged 70 or Older

Cardiac surgery was performed in 27 patients whose ages ranged from 70 to 78 years (mean, 72). In 17 of these patients, the operation was coronary artery bypass grafting without other procedures. There were 3 operative deaths (17.6 percent) but no late deaths during a mean follow‐up period of 14 months, and all the 14 surviving patients were improved symptomatically. In the other 10 of the 27 patients, the operation was valve replacement. There was no operative mortality among the 6 aortic valve patients and 1 operative death among the 4 mitral valve patients; the corresponding late deaths were 2 and 1, respectively, during a mean follow‐up period of 41.3 months. Improvements in operative management and improved criteria for the selection of patients should afford benefits and risks for elderly cardiac patients similar to those for younger cardiac patients.

Pheochromocytoma of the heart.

A patient with a pheochromocytoma involving the posterior wall of the left ventricle and the coronary sinus is reported. Complete surgical removal of the tumor was possible, although it caused a perioperative myocardial infarction. The literature regarding cardiac pheochromocytoma is reviewed.