657-662, 1984. A NUMBER of noninvasive methods for assessing right ventricular pressure have been developed based on physical examination results and the use of electrocardiograms, phonocardiograms, chest x-rays, and echocardiograms. ' '°While these methods can discriminate mild from severe right ventricular pressure elevation, they lack sufficient sensitivity to be useful in evaluating the effects of short-term therapeutic interventions or in monitoring the clinical course of outpatients.Recently The purpose of this study was to test the accuracy of the tricuspid gradient method in prospectively estimating right ventricular systolic pressures in a group of patients with Doppler-detected tricuspid regurgitation who underwent catheterization within 24 hr of their Doppler study. Material and methodsThe study group consisted of 62 patients in whom elevation of right-sided pressures was suspected on the basis of results of physical examination (loud pulmonic closure sound, right ventricular lift), chest x-ray (right ventricular enlargement, prominent pulmonary vasculature), and/or two-dimensional echocardiography (right ventricular chamber enlargement, "'D"-shaped left ventricle'0). Fifteen of the 62 patients were diagnosed as having clinical tricuspid regurgitation on the basis of results of physical examination by the primary ward physician. Criteria used for the clinical diagnosis of tricuspid regurgitation included systolic murmur with positive Carvallo's sign, prominent jugular venous "c-v" and hepatic pulsations, and right-sided S3. Specific criteria applied in a given case were not always stated in the medical record so we did not collate the incidence of such signs. The

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Background-A relatively simple, invasive method for quantitatively assessing the status of the coronary microcirculation independent of the epicardial artery is lacking. Methods and Results-By using a coronary pressure wire and modified software, it is possible to calculate the mean transit time of room-temperature saline injected down a coronary artery. The inverse of the hyperemic mean transit time has been shown to correlate with absolute flow. We hypothesize that distal coronary pressure divided by the inverse of the hyperemic mean transit time provides an index of microcirculatory resistance (IMR) that will correlate with true microcirculatory resistance (TMR), defined as the distal left anterior descending (LAD) pressure divided by hyperemic flow, measured with an external ultrasonic flow probe. A total of 61 measurements were made in 9 Yorkshire swine at baseline and after disruption of the coronary microcirculation, both with and without an epicardial LAD stenosis. The mean IMR (16.9Ϯ6.5 U to 25.9Ϯ14.4 U, Pϭ0.002) and TMR (0.51Ϯ0.14 to 0.79Ϯ0.32 mm Hg · mL Ϫ1 · min

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Background-Current treatment for acute myocardial infarction (AMI) focuses on reestablishing blood flow (reperfusion).Paradoxically, reperfusion itself may cause additional injury to the heart. We previously found that ␦-protein kinase C (␦PKC) inhibition during simulated ischemia/reperfusion in isolated rat hearts is cardioprotective. We focus here on the role for ␦PKC during reperfusion only, using an in vivo porcine model of AMI. Methods and Results-An intracoronary application of a selective ␦PKC inhibitor to the heart at the time of reperfusion reduced infarct size, improved cardiac function, inhibited troponin T release, and reduced apoptosis. Using 31 P NMR in isolated perfused mouse hearts, we found a faster recovery of ATP levels in hearts treated with the ␦PKC inhibitor during reperfusion only. Conclusions-Reperfusion injury after cardiac ischemia is mediated, at least in part, by ␦PKC activation. This study suggests that including a ␦PKC inhibitor at reperfusion may improve the outcome for patients with AMI. (Circulation. 2003;108:2304-2307.)Key Words: reperfusion Ⅲ cardioprotection Ⅲ kinases C urrent treatment for acute myocardial infarction (AMI) is aimed at limiting the duration of the ischemic period by disrupting the occlusion in the coronary artery. However, no therapeutic treatment is available to prevent reperfusion injury, which occurs after these interventions. 1,2 We previously developed several isozyme-selective inhibitor and activator peptides of protein kinase C (PKC). 3 Recently, we found that treatment with a ␦PKC-selective inhibitor during ischemia/reperfusion reduced cardiac damage in isolated perfused rat hearts. 3,4 Here, we show that the ␦PKC inhibitor prevented reperfusion injury in an in vivo porcine model of AMI. Methods Peptide SynthesisThe ␦PKC inhibitor peptide ␦V1-1 was synthesized and conjugated to Tat-derived peptide 5 via a cysteine S-S bond as described. 3 In Vivo Local Occlusion, Peptide Delivery, and Pathological AssessmentWe applied a balloon catheter into the mid left anterior descending coronary artery of female juvenile Yorkshire pigs (35 to 40 kg) under anesthesia (1% isoflurane) and inflated the balloon to produce a total occlusion for 30 minutes. The guide wire was removed, and Tat alone (Tat) or Tat-␦V1-1 conjugate (␦V1-1) was infused via the lumen of the balloon catheter only for the last 1 minute of ischemia (250 ng/kg, 1 mL/min). Left ventriculograms were performed to determine cardiac function. Hearts were harvested 4 hours or 5 days after ischemia. Double staining with Evans blue dye and TTC marked areas at risk for ischemia and infarcted areas, respectively, as described previously. 6 Troponin T levels in blood, as an indicator of cardiac cytolysis, were also determined after 24 hours of reperfusion.Wedge biopsies of liver, spleen, lung and kidney were fixed in 10% buffered neutral formalin and embedded in paraffin, and 8-m-thick sections were stained with hematoxylin and eosin for pathological examination. Biochemical Analysis of Porcine Cardiac TissueH...

Compared to standard measures, IMR appears to be a better predictor of microvascular damage after STEMI, both acutely and in short term follow-up.

Background. Atherosclerotic plaque fracture and dissection of the arterial wall are frequent concomitants of the balloon angioplasty process. The composition and morphology of plaque within the vessel may be critical in determining the extent of plaque fracture and dissection during balloon angioplasty. To

Intravascular ultrasound imaging is a new method in which high resolution images of the arterial wall are obtained with use of a catheter placed within an artery. An in vitro Plexiglas well model was used to validate measurements of the luminal area, and an excellent correlation was obtained. One hundred thirty segments of fresh peripheral arteries underwent ultrasound imaging and the findings were compared with the corresponding histopathologic sections. Luminal areas determined with ultrasound imaging correlated well with those calculated from microscopic slides (r = 0.98). Three patterns were identified on the ultrasound images: 1) distinct interface between media and adventitia, 2) indistinct interface between media and adventitia but different echo density layers, and 3) diffuse homogeneous appearance. The types of patterns depended on the relative composition of the media and adventitia. Calcification of intimal plaque obscured underlying structures. Atherosclerotic plaque was readily visualized but could not always be differentiated from the underlying media.