Left ventricular rupture complicating percutaneous mitral commissurotomy: salvage using percutaneous cardiopulmonary bypass support

Mechanisms of cardiac perforation leading to tamponade in balloon mitral valvuloplasty

Mechanisms of cardiac perforation in 10 cases of cardiac tamponade encountered in a single-center series of 903 balloon mitral valvuloplasty procedures were elucidated by precise localization of the site of perforation at subsequent surgery. These mechanisms were perforation of the aortic root and adjacent right atrium by sliding up of the transseptal set (2), apical tears by straight-tip balloon catheters driven distally during mitral valve dilatation (3), apical perforations by guidewires introduced through catheters wedged in the apex (2), tear of the posterior right atrial wall by dilatation of the track produced by very low septal punctures (2), and right ventricular perforation by a pacing catheter (1). Multivariate analysis showed cardiac perforation to be significantly related to the total experience at the center (inversely) and to patient age (directly). Left ventricular perforation occurred exclusively in patients > 40 yr of age. Understanding these mechanisms has enabled formulation of effective strategies to prevent cardiac perforation.

Gas-exchange function of a preprimed pediatric oxygenator stored for one year for emergency cardiopulmonary bypass

To save priming time and perform more rapid initiation of emergency cardiopulmonary bypass for acute cardiopulmonary failure, an extracorporeal circuit with a hollow-fiber oxygenator (EL-2000 for pediatric use; Kurary Co. Ltd., Osaka, Japan) was preprimed, and the gas-exchange function was evaluated after 1 year of storage. EL-2000 has a dense polyolefin membrane with a surface area of 0.3 m2. When the bypass flow rates were 250, 500, 1,000, and 1,500 ml/min with 100% oxygen at the same flow rate as the bypass blood flow (namely, V/Q = 1) to the oxygenator, oxygen transport rates of the stored oxygenator were 19.6 +/- 0.3, 38.3 +/- 0.41, 64.4 +/- 0.9, and 76.4 +/- 2.7 ml/min (n = 5, mean +/- SD), respectively. PCO2 differences between pre- and postoxygenator blood (delta PCO2) were 18.6 +/- 1.4, 12.0 +/- 1.6, and 4.4 +/- 1.2 mm Hg at V/Q = 1 and the same bypass blood flow rates, respectively, excluding 1,500 ml/min, the data for which were excluded because of preparatory failure. PCO2 removal indices (defined as the ratio of delta PCO2 to PCO2 in preoxygenator blood) were 0.45 +/- 0.03, 0.29 +/- 0.12, and 0.10 +/- 0.03, respectively. Though the evaluation was done using only a single oxygenator, we feel strongly that the gas-exchange function of the preprimed dense-membrane hollow fiber oxygenator will be preserved even after 1 year of storage.

Percutaneous introduction of left atrial cannula for left heart bypass: utility of biplane transesophageal echocardiographic guidance for transseptal puncture

For introduction of a left atrial (LA) cannula by the transseptal puncture technique, we examined the feasibility of using biplane transesophageal echocardiography (B-TEE). A transseptal puncture was performed on 15 patients (3 male; 12 female; mean age, 48.9 +/- 11.2 years) by B-TEE guide during percutaneous transvenous mitral comissurotomy (PTMC). The entire Brocken-brough needle and the position of its tip were clearly observed in the right atrium by a longitudinal image of B-TEE in all patients (100%), and in 2 (13%) of them also by the transverse image of B-TEE. The puncture was about 1 cm caudal from the center of the fossa ovalis to avoid any large residual atrial septal defect. After transseptal puncture, a Mullin's sheath (7 Fr) and a dilator (14 Fr) were inserted into the left atrium in order, and then an Inoue's balloon catheter (12 Fr) was introduced without difficulty into the left atrium in all patients. With contrast injection, the position of the sheaths's tip was clearly confirmed by B-TEE. Left heart bypass support (left atrial-femoral artery bypass or AAB) was performed on 2 patients after percutaneous introduction of the LA cannula using this technique, and both were successfully supported and survived. With B-TEE guidance, the Brockenbrough atrial septal puncture and introduction of the LA cannula into left atrium can be performed easily. Thus, percutaneous left heart bypass can be set up quickly and safely even in an intensive care unit or outpatient emergency room without radiographic guidance.

Comparison between single (Inoue) and double balloon mitral valvuloplasty: immediate and short-term results

This study compared the results in 60 consecutive patients with severe rheumatic mitral stenosis, who underwent percutaneous double-balloon mitral valvuloplasty by means of a combination of 20 mm + 20 mm diameter balloon catheters (group A), with a similar group of 60 consecutive patients who underwent single (Inoue) balloon mitral valvuloplasty (group B). After balloon mitral valvuloplasty the hemodynamic measurements showed significant improvement in both groups: in groups A and B, respectively, mitral valve area calculated with the Gorlin formula increased from 0.9 +/- 0.2 to 2.1 +/- 0.5 cm2 (p less than 0.001) and from 0.8 +/- 0.2 to 1.9 +/- 0.4 cm2 (p less than 0.001). There was a significant improvement in cardiac functional status in both groups. There was no significant difference between the groups with regard to clinical or hemodynamic improvement, technical failure rate, inadequacy of dilatation, or complications. However, the double-balloon technique was more complex and involved a longer screening time--group A, 40 +/- 12 minutes; group B, 21 +/- 10 minutes (p less than 0.001). In our institution the disposable supplies used for the Inoue balloon technique were 40% more expensive than those used for the double-balloon technique.

Left ventricular perforation during percutaneous balloon mitral valvuloplasty

Percutaneous balloon mitral valvuloplasty has been reported to be complicated by left ventricular perforation with fatal results. We report two cases of left ventricular perforation following balloon mitral valvuloplasty. In one patient left ventricular perforation occurred silently without any hemodynamic sequelae and was only detected at left ventricular angiography after valvuloplasty. In the second patient left ventricular perforation was caused by the mitral dilating balloon catheter. The subsequent tamponade was relieved by immediate aspiration with hemodynamic stabilization thereafter. Neither patient required surgery. Both patients are well 6 mon after the procedure. We discuss the mechanism of this serious complication in these two patients.

Valve deformity and balloon mechanics in percutaneous transvenous mitral commissurotomy

Percutaneous transvenous mitral commissurotomy (PTMC) using balloon catheters has emerged as an alternative therapeutic modality for patients with mitral stenosis. When used initially in the United States, a single balloon, designed for peripheral arterial angioplasty, was passed across the intraatrial septum for mitral dilatation. The results were less than ideal, with resultant valve areas between 1.0 and 1.5 cm2. Double balloon dilatation was introduced and yielded valve areas between 1.5 and over 2.0 cm2. However, the double balloon technique is substantially more cumbersome, requires passage of two catheters through the atrial septum with an incidence of atrial septal defect, and results in significant hemodynamic sequelae during the procedure. This report describes a novel single balloon for PTMC. In contrast to the more conventionally used peripheral arterial balloons, this device was specifically designed for mitral stenosis. Results in 25 patients (mean age 60 +/- 5 years; range 29 to 87 years) showed an increase in value area from 0.9 +/- 0.2 cm2 to 1.6 +/- 0.5 cm2 (p less than 0.001). In contrast to the results reported with conventional balloon dilatation, there was no difference in the resultant valve area or in the incidence of complications among patients with more severely deformed valves compared with patients with more "ideal" valves for commissurotomy. An in vitro comparison of the pressure-volume characteristics of the conventional versus the Inoue balloon showed the latter to be more compliant, reaching nominal inflated diameter at 2.0 +/- 0.4 atm versus 3.3 +/- 0.5 atm for conventional balloons (p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)