Recovery of distal coronary flow reserve in LAD and LCx after Y-Graft intervention assessed by transthoracic echocardiography.

BACKGROUND: Y- graft (Y-G) is a graft formed by the Left Internal Mammary Artery (LIMA) connected to the Left Anterior Descending Artery (LAD) and by a free Right Internal Mammary Artery (RIMA) connected to LIMA and to a Marginal artery of Left Circumflex Artery (LCx). Aim of the work was to study the flow of this graft during a six months follow-up to assess whether the graft was able to meet the request of all the left coronary circulation, and to assess whether it could be done by evaluation of coronary flow reserve (CFR). METHODS: In 13 consecutive patients submitted to Y-G (13 men), CFR was measured in distal LAD and in distal LCx from 1 week after , every two months, up to six months after operation (a total of 8 tests for each patient) by means of transthoracic echocardiography (TTE) and Adenosine infusion (140 mcg/kg/min for 3-6 min). A Sequoia 256, Acuson-Siemens, was used. Contrast was used when necessary (Levovist 300 mg/ml solution at a rate of 0,5-1 ml/min). Max coronary flow diastolic velocity post-/pre-test > or =2 was considered normal CFR. RESULTS: Coronary arteriography revealed patency of both branches of Y-G after six months. Accuracy of TTE was 100% for LAD and 85% for LCx. Feasibility was 100% for LAD and 85% for LCx. CFR improved from baseline in LAD (2.21 +/- 0.5 to 2.6 +/- 0.5, p = 0.03) and in LCx (1.7 +/- 1 to 2.12 +/- 1, p = 0.05). CFR was under normal at baseline in 30% of patients vs 8% after six months in LAD (p = 0.027), and in 69% of patients vs 30% after six months in LCx (p = 0.066). CONCLUSION: CFR in Y-G is sometimes reduced in both left territories postoperatively but it improves at six months follow-up. A follow-up can be done non-invasively by TTE and CFR evaluation.

Identification of myocardial and vascular precursor cells in human and mouse epicardium.

During cardiac development, the epicardium is the source of multipotent mesenchymal cells, which give rise to endothelial and smooth muscle cells in coronary vessels and also, possibly, to cardiomyocytes. The aim of the present study was to determine whether stem cells are retained in the adult human and murine epicardium and to investigate the regenerative potential of these cells following acute myocardial infarction. We show that c-kit(+) and CD34(+) cells can indeed be detected in human fetal and adult epicardium and that they represent 2 distinct populations. Both subsets of cells were negative for CD45, a cell surface marker that identifies the hematopoietic cell lineage. Immunofluorescence revealed that freshly isolated c-kit(+) and CD34(+) cells expressed early and late cardiac transcription factors and could acquire an endothelial phenotype in vitro. In the murine model of myocardial infarction, there was an increase in the absolute number and proliferation of epicardial c-kit(+) cells 3 days after coronary ligation; at this time point, epicardial c-kit(+) cells were identified in the subepicardial space and expressed GATA4. Furthermore, 1 week after myocardial infarction, cells coexpressing c-kit(+), together with endothelial or smooth muscle cell markers, were identified in the wall of subepicardial blood vessels. In summary, the postnatal epicardium contains a cell population with stem cell characteristics that retains the ability to give rise to myocardial precursors and vascular cells. These cells may play a role in the regenerative response to cardiac damage.

Feasibility and efficacy of minimally invasive stand-alone surgical ablation of atrial fibrillation. A single-center experience.

PURPOSE: Minimally invasive surgical ablation for atrial fibrillation (AF) has shown good results and low complications incidence. Our objective was to evaluate feasibility and efficacy of this technique in our center. METHODS: The procedure included pulmonary vein isolation, ganglionic plexi ablation, ligament of Marshall resection, and left atrial appendage exclusion through beating heart minimally invasive bilateral thoracotomies. Patients were monitored daily by telemedicine during the first 4 months and then by quarterly 24-h Holter monitoring or by implantable cardiac monitor. Ablation success was defined as freedom from any atrial tachyarrhythmia recurrence lasting more than 30 s and from antiarrhythmic drugs. All patients were followed up for a minimum of 12 months. RESULTS: Twenty-two consecutive patients with AF, paroxysmal in 27% and persistent in 73%, were treated. Mean age was 63 ± 10 years, 86% were men. Seventy-three percent of patients had previously undergone to one or more catheter ablations. Median follow-up period was 22 months (25°-75° percentile, 20-27). Patients free from any arrhythmia recurrence for at least 6 consecutive months discontinued antiarrhythmic therapy. Ablation was successful in 73% of patients at 12 months. Freedom from AF recurrences independently from antiarrhythmic therapy status was 91% at 12 months. Results were consistent in patients that reached 24 months follow-up. There were no deaths. Complications were: one conversion to sternotomy owing to thoracic adherences, one pacemaker implant, and one postoperative hemothorax requiring surgical revision. CONCLUSIONS: Our results show that minimally invasive surgical ablation was feasible and gave satisfactory results at long-term term follow-up in patients with AF.