Cardiovascular magnetic resonance: current clinical practice and future potential.

Cardiovascular magnetic resonance (CMR) is playing an increasing role in the noninvasive assessment of the cardiothoracic patient. It provides rapid, high-resolution anatomical coverage, and accurate functional cardiovascular assessment without the need for ionizing radiation. In this article, we discuss the fundamental principles of CMR and outline the established and newer indications for its use. Finally, the future potential for this technique in the cardiovascular arena is briefly outlined.

Effects of radial stretch on target lesion revascularization after percutaneous coronary intervention: an intravascular ultrasound study.

OBJECTIVE: To analyze possible associations between radial stretch during coronary angioplasty and the incidence of target lesion revascularization (TLR). PATIENTS AND METHODS: Intravascular ultrasound images were obtained before and after revascularization in 182 native coronary lesions. The quantitative intravascular ultrasound parameters (external elastic membrane cross-sectional area [EEM-A], lumen areas [LA], plaque area [PA], calculated as EEM-A-LA, and changes between pre- and postinterventional LA [DLA], EEM-A [DEEM-A] and PA [DPA]) were correlated with the incidence of TLR. RESULTS: TLR was performed in 60 (33%) patients, while 122 (67%) patients remained event free. Postinterventional PA remained significantly larger in the TLR group than in the event-free group (9.2 +/- 3.3 mm2 versus 7.9 +/- 3.3 mm2; P=0.02). The radial stretch during intervention, expressed as DEEM-A, and the balloon to artery ratio was significantly larger in the TLR group (DEEM-A: 1.9 +/- 2.1 mm2 versus 1.3 +/- 2.0 mm2; P=0.03; balloon to artery ratio: 1.3 +/- 0.2 versus 1.0 +/- 0.5; P=0.04). Multivariate analysis revealed DEEM-A (P=0.01), DPA (P=0.03), diabetes (P=0.001, odds ratio 5.2, 95% CI 4.9 to 6.5) and adaptive remodelling (P<0.001, odds ratio 4.1, 95% CI 3.5 to 6.4) as independent predictors for TLR. CONCLUSION: Whereas patients in whom lumen gain is achieved primarily by plaque reduction with less wall stretch tend to remain event free, patients with significant radial stretch (ie, less reduction of the PA, but a radial outward shift of the plaque mass) experience a higher incidence of TLR.

Intravenous magnesium sulphate in acute myocardial infarction--is the answer "MAGIC"?

The role of magnesium in coronary artery disease has been evaluated extensively during the last three decades. The intravenous application of magnesium in acute myocardial infarction is of major importance, the beneficial effects have been underlined in several studies. Magnesium is of significance in the pathomechanisms of reperfusion injury and reduction of malign arrhythmias in the critical acute phase of myocardial infarction, if applied intravenously. However, the promising results of LIMIT-2 could not be confirmed by the data of ISIS-4. The timing of magnesium therapy is probably the most important key factor. Similar to the guidelines of thrombolytic intervention, magnesium has to be administered as early as possible, at the latest before myocardial reperfusion has started. Nevertheless, because of conflicting results of prior trials doubts on the efficacy of intravenous magnesium in myocardial infarction still remain. The multinational, multicenter trial MAGIC has been set up to evaluate the optimal patient cohort as well as the ideal dose regimen for the application of intravenous magnesium sulphate in patients with acute myocardial infarction. The answer on the open questions on intravenous magnesium sulphate in myocardial infarction could be "MAGIC".

Intimal hyperplasia and coronary flow reserve after heart transplantation: association with big endothelin-1.

BACKGROUND: Endothelin, a peptide with strong vasoconstrictive and mitogenic properties, has been found to increase after cardiac transplantation. We therefore assessed the association between its precursor peptide, big endothelin-1, and intimal hyperplasia and coronary flow reserve after heart transplantation. METHODS: Thirty-five patients without hemodynamically significant coronary artery disease after heart transplantation were investigated: Average peak flow velocity in the left anterior descending artery (LAD) was assessed by intracoronary Doppler at baseline as well as after injection of adenosine; coronary flow reserve was calculated as a ratio of both and was corrected for patient age and baseline average peak flow velocity. Lumen, intima + media and total vessel area were measured by intracoronary ultrasound. The plasma concentration of big endothelin-1 in venous blood was determined by radioimmunoassay. RESULTS: Patients with elevated big endothelin-1 levels (>2 fmol/ml) tended to have a decreased corrected coronary flow reserve (2.60 +/- 0.9 vs 3.21 +/- 1.0, p = 0.078). They also had a significantly larger intima + media area (5.82 +/- 2.9 vs 2.37 +/- 2.9 mm(2), p = 0.004) and total vessel area (18.36 +/- 5.8 vs 12.81 +/- 4.8 mm(2), p = 0.012) than those with normal plasma concentrations. CONCLUSIONS: Our study suggests an association between elevated big endothelin-1 plasma levels and the development of intimal hyperplasia and reduction of coronary flow reserve after cardiac transplantation.

Short- and long-term results of emergency and elective percutaneous interventions on left main coronary artery stenoses.

In this prospective study, we analyzed the short- and long-term outcomes of percutaneous interventions on significant left main coronary artery (LM) stenoses. Between January 1998 and June 2000, 18 patients underwent emergency interventions on unprotected LM stenoses (group 1), while 15 patients had elective interventions on protected LM stenoses (group 2). Despite a procedural success of 88.9% in group 1, event-free in-hospital and mortality rates were 50.0% and 38.9%. After 6.4 +/- 4.4 months of follow-up, late event-free survival and mortality rates were 33.3% and 38.9%. In group 2, procedural success was 100%, with 100% event-free in-hospital survival; late event-free survival and mortality rates were 93.3% and 0% after 6.7 +/- 4.1 months of follow-up. Emergency interventions on LM stenoses remain a procedure with high acute and mid-term mortality. In spite of the high rate of major adverse cardiac events, an acceptable long-term survival can be achieved.