Influence of left ventricular hypertrophy on microvascular dysfunction and left ventricular remodelling after acute myocardial infarction.

AIMS: To ascertain whether the presence of left ventricular (LV) hypertrophy in patients with ST-segment elevation myocardial infarction (STEMI) influences microvascular dysfunction and LV remodelling at 6 months of follow-up. METHODS AND RESULTS: Fifty-six consecutive STEMI patients successfully treated with primary or rescue percutaneous coronary intervention underwent conventional two-dimensional and myocardial contrast echocardiography within 24 h and at 6 months. Left ventricular mass, end-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction, and wall motion score index (WMSI) were measured. Left ventricular hypertrophy was defined as LV mass index >116 g/m(2) in men and >104 g/m(2) in women. In order to evaluate the potential influence of microvascular dysfunction on LV remodelling, myocardial perfusion was semiquantitatively scored by contrast score index (CSI). Patients with LV hypertrophy had higher EDV and ESV both at 24 h and at 6 months, compared with patients without LV hypertrophy (P < 0.05). No significant changes over time were observed in both groups. Both WMSI and CSI were similar between groups at 24 h and at follow-up, but improved in both groups over time (P < 0.05). CONCLUSION: Left ventricular hypertrophy does not appear to influence the development of post-acute myocardial infarction LV remodelling. Hypertrophic and non-hypertrophic left ventricles showed the same extent and temporal improvement in regional contractile function and microvascular perfusion.

Reversible microvascular dysfunction coupled with persistent myocardial dysfunction: implications for post-infarct left ventricular remodelling.

BACKGROUND: Recent studies have shown that microvascular dysfunction after myocardial infarction is a dynamic phenomenon. AIMS: To evaluate the implications of dynamic changes in microvascular dysfunction on contractile recovery and left ventricular remodelling, and to identify the ideal timing of assessment of such microvascular dysfunction. METHODS AND RESULTS: In 39 patients with a first myocardial infarction who underwent successful percutaneous coronary intervention, microvascular dysfunction was studied by myocardial contrast echocardiography (MCE) at 24 h, 1 week and 3 months after the procedure. Real-time MCE was performed by contrast pulse sequencing and intravenous Sonovue. 14 patients exhibited left ventricular remodelling at 3 months (>20% increase in left ventricular end-diastolic volume, group B), whereas 25 did not (group A). Microvascular dysfunction was similar in the two groups at 24 h and improved in group A only, being significantly better than that of group B at 1 week (p<0.05) and 3 months (p<0.005). Improvement in microvascular dysfunction was not associated with improvement in wall motion in the same segments. With multivariate analysis including all echocardiographic variables, microvascular dysfunction at 1 week was found to be the only independent predictor of left ventricular remodelling (p<0.01). With a cut-off value of 1.4, 1-week microvascular dysfunction predicts left ventricular remodelling with sensitivity and specificity of 73%. CONCLUSIONS: Improvement in microvascular dysfunction occurs early after myocardial infarction, although it is not associated with a parallel improvement in wall motion but is beneficial in preventing left ventricular remodelling. Accordingly, 1-week microvascular dysfunction is a powerful and independent predictor of left ventricular remodelling.

Use of a novel high-osmolar gadolinium chelate, gadobutrol, for percutaneous renal artery stenting in two patients with chronic renal failure.

Gadolinium chelates have been recently proposed and preliminarily tested as contrast agents for diagnostic and interventional angiography in alternative to iodinated media. However, in most studies low-osmolarity agents were employed and digital subtraction was required for satisfactory images. In this article, we report for the first time in the literature two cases of successful percutaneous renal artery stenting in which gadobutrol, a high-osmolar (1 mmol/ml) gadolinium chelate, was employed as contrast agent because of chronic renal failure and substantial risk for iodinated contrast-associated nephrotoxicity. In both patients gadobutrol yielded high-quality images without digital subtraction and was well tolerated with no ensuing renal dysfunction.