Effect of the ratio of coronary arterial lumen volume to left ventricle myocardial mass derived from coronary CT angiography on fractional flow reserve.

BACKGROUND: We hypothesize that in patients with suspected coronary artery disease (CAD), lower values of the ratio of total epicardial coronary arterial lumen volume to left ventricular myocardial mass (V/M) result in lower fractional flow reserve (FFR). METHODS: V/M was computed in 238 patients from the NXT trial who underwent coronary computed tomography angiography (CTA), quantitative coronary angiography (QCA) and FFR measurement in 438 vessels. Nitroglycerin was administered prior to CT, QCA and FFR acquisition. The V/M ratio was quantified on a patient-level from CT image data by segmenting the epicardial coronary arterial lumen volume (V) and the left ventricular myocardial mass (M). Calcified and noncalcified plaque volumes were quantified using semi-automated software. RESULTS: The median value of V/M (18.57 mm3/g) was used to define equal groups of low and high V/M patients. Patients with low V/M had greater diameter stenosis by QCA, more plaque and lower FFR (0.80 ± 0.12 vs. 0.87 ± 0.08; P < 0.0001) than those with high V/M. A total of 365 vessels in 202 patients had QCA stenosis ≤50% and measured FFR. In these patients, those with low V/M had higher percent diameter stenosis by QCA, greater total plaque volume and lower FFR (0.81 ± 0.12 vs. 0.88 ± 0.07; P < 0.0001) than those with high V/M. In multivariate logistic regression analysis, V/M was an independent predictor of FFR ≤0.80 (all p-values < 0.001). CONCLUSIONS: Patients with a low V/M ratio have lower FFR overall and in non-obstructive CAD, independent of plaque measures.

Mitral repair with the Evalve MitraClip device: histopathologic findings in the porcine model.

INTRODUCTION: Percutaneous mitral repair with the MitraClip device ("clip") is currently being evaluated in a Phase II clinical trial (EVEREST II). This device was evaluated in an animal model prior to use in humans. MATERIALS AND METHODS: Twenty-one excised clips with accompanying leaflet tissue from pigs were examined at 4, 12, 17, 24, and 52 weeks. Sixteen specimens were available for hematoxylin and eosin and Movat pentachrome staining, and five were sent for scanning electron microscopy. The devices were examined grossly for tissue growth on flow and nonflow surfaces, thrombus, and vegetations. Microscopic evaluation focused on the presence of tissue growth around the device, the inflammatory response, and the presence of thrombus, infective endocarditis, and hematoma. RESULTS: Tissue growth on both flow and nonflow surfaces was seen in all specimens with variation of tissue thickness proportional to the duration of device implantation. Evidence of endothelialization, fibrous encapsulation, and organization of tissue between the aortic and mitral leaflets was observed. Adjacent chordae tendinae were incorporated into the healing tissue growth around the device as early as 4 weeks, in 33% of clips implanted for that time period, increasing to 67% of clips at 12 weeks, and 100% of clips at 17, 24, and 52 weeks. Two animals were diagnosed with infective endocarditis during life. CONCLUSIONS: Mechanical coaptation of the mitral leaflets in an animal model demonstrates adequate tissue response and healing with complete encapsulation of the device by 12 weeks and ongoing healing response proportional to duration of implantation. Infective endocarditis remains a potential complication in the animal model and for all implanted prosthetic devices.

Percutaneous treatment of valvular heart disease: catheter-based aortic valve replacement and mitral valve repair therapies.

Until recently, percutaneous catheter therapy for valvular heart disease was limited to catheter balloon valvuloplasty for aortic, mitral, or pulmonic stenosis. A number of new approaches to percutaneous valve therapy are now developing rapidly, including methods for catheter-based valve replacement and repair. Stent-mounted valve prostheses have been successfully implanted in the pulmonic and aortic positions. These devices have been constructed using pericardial valve leaflets mounted inside balloon-expandable or self-expanding stents and have been used in patients who are high risk for valve replacement surgery. Percutaneous valve repair is also being developed for mitral regurgitation. Direct leaflet repair and percutaneous annuloplasty are being employed in clinical trials. All the percutaneous approaches are based on existing surgical techniques and offer less invasive alternatives. The era of percutaneous valve therapy has clearly arrived, and ongoing trials will define the clinical role for these new therapies.

Percutaneous mitral valve repair using the edge-to-edge technique: six-month results of the EVEREST Phase I Clinical Trial.

OBJECTIVES: This study sought to evaluate the clinical results of a percutaneous approach to mitral valve repair for mitral regurgitation (MR). BACKGROUND: A surgical technique approximating the middle scallops of the mitral leaflets to create a double orifice with improved leaflet coaptation was introduced in the early 1990s. Recently, a percutaneous method to create the same type of repair was developed. A trans-septal approach was used to deliver a clip device that grasps the mitral leaflet edges to create the double orifice. METHODS: General anesthesia, fluoroscopy, and echocardiographic guidance are used. A 24-F guide is positioned in the left atrium. The clip is centered over the mitral orifice, passed into the left ventricle, and pulled back to grasp the mitral leaflets. After verification that MR is reduced, the clip is released. RESULTS: Twenty-seven patients had six-month follow-up. Clips were implanted in 24 patients. There were no procedural complications and four 30-day major adverse events: partial clip detachment in three patients, who underwent elective valve surgery, and one patient with post-procedure stroke that resolved at one month. Three additional patients had surgery for unresolved MR, leaving 18 patients free from surgery. In 13 of 14 patients with reduction of MR to < or =2+ after one month, the reduction was maintained at six months. CONCLUSIONS: Percutaneous edge-to-edge mitral valve repair can be performed safely and a reduction in MR can be achieved in a significant proportion of patients to six months. Patients who required subsequent surgery had elective mitral valve repair or intended replacement.