Keywords
INTRODUCTION
William Harvey was the first to describe rupture of the left ventricular (LV) free wall, in the year 1647. Currently, a combination of clinical, echocardiographic, and hemodynamic criteria are applied to establish the diagnosis of subacute cardiac rupture.1-5 Urgent surgical repair is the treatment indicated in these cases.6 However, it is unknown whether pericardial manipulation and the use of patches might have consequences on LV function at medium term.7-18
In this study, we evaluate the evolution of LV function and the development of evidence of pericardial constriction at medium term in patients with subacute rupture treated surgically.
METHODS
Study Population
From 2006 to 2008, 11 patients admitted to the coronary unit of our hospital were diagnosed of subacute rupture of the LV free wall following myocardial infarction. The condition was confirmed during exploratory surgery and repaired in the same procedure. Six of the 11 patients were followed-up to medium term. In the remaining 5 patients, follow-up was not completed: 2 died (one due to myocardial infarction and the other, bilateral pneumonia) and 3 were lost to follow-up.
Echocardiographic Study at the Time of the Diagnosis
Because of the extreme severity of the clinical picture, the initial study was carried out with the most immediately available echocardiography system.
Echocardiographic Study During Follow-up
All patients underwent 2D Doppler echocardiography with a Philips IE-33 system and S5-1 transducer (Philips, Bothell, Was hington, USA). A complete evaluation of systolic and diastolic function was performed and signs of pericardial constriction were investigated.
A 3D echocardiographic study was carried out immediately after the conventional study, using a Philips X3-1 transducer (Philips, Bothell, Washington, USA). The 3D images were acquired from the apical window using a complete volume technique, stored in a central server, and analyzed off-line with Q-Lab (version 6.0) software9 (Philips, Bothell, Washington, USA).
The criteria used to establish the diagnosis of constrictive pericarditis by Doppler echocardiography were ≥25% respiratory variation in peak mitral E-wave velocity at inflow and an increase in reverse diastolic flow in the hepatic veins or vena cava on expiration.
Statistics
Statistical calculations were performed with SPSS 11.0 (SPSS Inc., Chicago, Illinois). Quantitative data are expressed as the mean (standard deviation) and/or the median [interquartile interval]. Qualitative data are expressed as absolute number (percentage). The Student t test or Wilcoxon test were used for comparisons of parametric quantitative data.
RESULTS
Six of the 11 patients could be completely followed-up and assessed (Table 1). Median age was 71.5 [17] years and 4 (66%) were men. Median duration of follow-up was 7 [18] months, mean, 7.9 (11.2) months. All patients were treated with beta-blockers. None were treated with thrombolysis.
The diagnosis was established within the first 24 hours in 75% of patients. At the time of the diagnosis, all patients were hemodynamically unstable and showed syncope or presyncope on echocardiography, together with hemodynamic evidence of tamponade; 3 patients had findings consistent with cardiogenic shock.
The most common cardiovascular risk factors were hypertension (3 patients; 50%), smoking (3 patients; 50%), and diabetes mellitus (3 patients; 50%). The infarct was in an anterior location in 5 (83.3%) patients, and only 1 patient (16.7%) had had a previous infarct. Coronary angiography was performed before surgery in half the patients (n=3). One patient (16.7%) showed significant single-vessel disease that was revascularized in the same procedure as repair of the rupture, and 2 others presented significant 3-vessel disease, which was revascularized in 1 case. The rupture repair technique involved direct repair without support from on-pump circulation. The rupture area was identified and a heterologous pericardial patch (Peri-Guard, Synovis Life Technologies, Inc.) was cut to an appropriate size for coverage. Biological glue (2-octyl cyanoacrylate; Dermabond, Ethicon Inc.) was applied to one of the surfaces of the patch and the rupture area was then covered.
Echocardiographic Study at the Time of the Diagnosis
Echocardiography performed before the intervention showed moderate or severe pericardial effusion in all patients with evident signs of cardiac tamponade. Left-ventricular ejection fraction (LVEF) values and LV volume results are shown in Table 2. Quantitative assessment of LVEF was carried out a posteriori from digitized images using the modified Simpson method.
2D and 3D Echocardiographic Studies at Medium-Term Follow-up
The echocardiography results at the end of follow-up are shown in Table 2. No echocardiographic findings consistent with constrictive pericarditis were present in any of the studies. Comparison of the LVEF values before and after surgery did not show statistically significant differences (P=.7).
DISCUSSION
The present study reports for the first time echocardiographic findings of LV function at medium-term follow-up of surgical repair of subacute rupture of the ventricular free wall. The data obtained show that the technique used does not affect systolic or diastolic LV function. Furthermore, there was no evidence of constrictive pericarditis, despite the fact that the procedure involves pericardial manipulation and placement of bovine pericardial patches.
The medium-term follow-up of patients with LV free wall rupture has been described in some studies, but there are few reported Doppler echocardiography findings. It is noteworthy that the follow-up results of our patients (Table 2) do not indicate significant deterioration of diastolic function. Also of note in our series, 4 patients were diagnosed in the first 24 hours after the onset of symptoms; that is, they had a very early presentation.
Limitations
The main limitation of the study is the small number of patients included. Nevertheless, because of the low prevalence of this condition, this study contains one of the largest series in the literature. Another limitation is the lack of data available from the preoperative echocardiography study. In addition, there could be a relationship between the size of the patch and the degree of constriction, but the exact patch size could not be measured because of the urgent nature of the surgery. Lastly, the volume measurements obtained with 2D echocardiography in the preoperative study are not exactly equivalent to those measured with 3D echocardiography at follow-up.
In conclusion, surgical repair of subacute LV free wall rupture is safe at medium-term and is not associated with sequelae related to LV function or the development of constrictive pericarditis. This is the largest series in which the middle-term follow-up findings of surgically treated subacute ruptures have been studied.
Correspondence: Dr. J.L. Zamorano.
Unidad de Imagen Cardiovascular. Hospital Clínico San Carlos. Prof. Martín Lagos, s/n. 28040 Madrid. España.
E-mail: jlzamorano@vodafone.es
Received October 20, 2008.
Accepted for publication March 11, 2009.