Invasive evaluation of plaque morphology of symptomatic superficial femoral artery stenoses using combined near-infrared spectroscopy and intravascular ultrasound.

The purpose of this study is to characterize the plaque morphology of severe stenoses in the superficial femoral artery (SFA) employing combined near-infrared spectroscopy and intravascular ultrasound (NIRS-IVUS). Atherosclerosis is the most common cause of symptomatic peripheral arterial disease. Plaque composition of SFA stenoses has been characterized as primarily fibrous or fibrocalcific by non-invasive and autopsy studies. NIRS has been validated to detect lipid-core plaque (LCP) in the coronary circulation. We imaged severe SFA stenoses with NIRS-IVUS prior to revascularization in 31 patients (46 stenoses) with Rutherford claudication ⩾ class 3. Angiographic parameters included lesion location and stenosis severity. IVUS parameters included plaque burden and presence of calcium. NIRS images were analyzed for LCP and maximum lipid-core burden index in a 4-mm length of artery (maxLCBI4mm). By angiography, 38 (82.6%) lesions were calcified and 9 (19.6%) were chronic total occlusions. Baseline stenosis severity and lesion length were 86.0 ± 11.0% and 36.5 ± 46.5 mm, respectively. NIRS-IVUS identified calcium in 45 (97.8%) lesions and LCP in 17 (37.0%) lesions. MaxLCBI4mm was 433 ± 244. All lesions with LCP also contained calcium; there were no non-calcified lesions with LCP. In conclusion, this is the first study of combined NIRS-IVUS in patients with PAD. NIRS-IVUS demonstrates that nearly all patients with symptomatic severe SFA disease have fibrocalcific plaque, and one-third of such lesions contain LCP. These findings contrast with those in patients with acute coronary syndromes, and may have implications regarding the pathophysiology of atherosclerosis in different vascular beds.

Analysis of target lesion length before coronary artery stenting using angiography and near-infrared spectroscopy versus angiography alone.

Lipid core plaque (LCP) can extend beyond the angiographic margins of a target lesion, potentially resulting in incomplete lesion coverage. We sought to compare the target lesion length using near-infrared spectroscopy (NIRS) combined with conventional coronary angiography versus angiography alone. NIRS was performed in 69 patients (75 lesions) undergoing native vessel percutaneous coronary intervention (LipiScan Coronary Imaging System). Chemograms were analyzed for the presence and location of LCP, either within or extending beyond, the angiographic margins of the target lesion. The target lesion length was measured by quantitative coronary angiography (QCA) and compared to the lesion length measured using QCA and NIRS. LCP was present in 50 target lesions (67%). In 42 lesions (84%), LCP was present only within the target lesion. In 8 lesions (16%) LCP extended beyond the angiographic margins of the lesion. Of these 8 lesions, 4 (8%) had LCP ≤5 mm from the margins, and 4 lesions (8%) had LCP >5 mm from the angiographic margins. The mean distance that the LCP extended beyond the angiographic lesion margin was 7 ± 4 mm (range 2 to 14). For these 8 lesions, the target lesion length with NIRS plus QCA was 28 ± 10 mm versus 21 ± 8 mm with QCA alone. In conclusion, patients undergoing coronary artery stenting could have LCP extending beyond the intended treatment margins as defined using QCA alone. This could have implications for stent length selection and optimal lesion coverage.

Malignant ventricular arrhythmias in patients with acute right ventricular infarction undergoing mechanical reperfusion.

Patients with acute right ventricular (RV) infarctions are prone to ventricular arrhythmias, but little is known regarding the temporal patterns of these arrhythmias, their impact on outcomes, or their relation to the severity of RV impairment. The aim of this study was to examine the impact of malignant ventricular arrhythmias (MVAs) complicating acute RV infarction. A further aim was to determine whether the degree of RV impairment was a predisposing factor to MVAs. The charts of 48 patients with acute RV infarctions were reviewed for documented MVAs. Temporal presentation, relating to reperfusion, and in-hospital outcomes were tabulated. Echocardiograms were reviewed to quantify RV impairment. MVAs occurred in 38% of patients, with multiple episodes (electrical storm) in 8.3%. MVAs developed before reperfusion (72% of patients), abruptly with reperfusion (11%), or after reperfusion (22%). Patients with MVAs had larger infarcts (peak creatine phosphokinase 3,027 vs 1,848 U/L, p = 0.03) and trended toward worse RV function (fractional shortening 27% vs 34%, p = 0.08). In-hospital mortality (patients with MVAs 17% vs 6.7%, p = 0.35), intensive care days (patients with MVAs 7.1 +/- 10 vs 3.9 +/- 2.5, p = 0.39), and hospital days (patients with MVAs 10.3 +/- 10 vs 8.0 +/- 5.1, p = 0.57) were similar between groups. Patients with electrical storm had longer intensive care stays (18.0 +/- 18.5 vs 4.0 +/- 2.5 days, p = 0.02) and hospital stays (20.5 +/- 17 vs 7.9 +/- 5.0 days, p = 0.05). In conclusion, MVAs are common in acute RV infarctions. They frequently occur before reperfusion and are associated with larger infarcts. With reperfusion, MVAs had little impact on intensive care and hospital stays or in-hospital mortality, except in patients with electrical storm.

Patterns of coronary compromise leading to bradyarrhythmias and hypotension in inferior myocardial infarction.

BACKGROUND: Occlusion and reperfusion of the acutely occluded right coronary artery may result in abrupt bradycardia and hypotension, attributed to Bezold-Jarisch cardio-inhibitory reflexes arising from the ischemic left ventricle. Given that right ventricular infarction, a result of proximal right coronary artery occlusion, predisposes to bradycardia and hypotension, we hypothesized that proximal right coronary occlusions would be more likely to result in bradycardia-hypotension compared to more distal occlusions. METHODS: In 216 patients with acute inferior myocardial infarction undergoing primary angioplasty of the right coronary artery, we retrospectively analyzed the incidence of bradyarrhythmias and hypotension during occlusion and with reperfusion. RESULTS: Occlusion proximal to the right ventricular branches was identified in 151 (70%) of cases, with occlusions distal but compromising the left ventricular and atrioventricular nodal branches in 65 (30%) others. During occlusion, those with proximal occlusions were more likely to suffer hypotension (41 versus 15%, P=0.0002), advanced atrioventricular block (21 versus 3%, P=0.0008) and hypotension with bradycardia (25 versus 9%, P=0.01). Similarly, reperfusion of proximal occlusions more frequently resulted in abrupt hypotension (42 versus 19%, P=0.002), bradycardia (34 versus 14%, P=0.004) and hypotension with bradycardia (27 versus 12%, P=0.02). CONCLUSIONS: These data demonstrate that during right coronary artery occlusion and with reperfusion, bradycardia and hypotension develop more commonly in patients with proximal occlusions compared with those with distal occlusions. These findings suggest that reflexes arising from the ischemic right ventricle may play a role in bradyarrhythmias and hypotension.

Resolution of refractory no-reflow with intracoronary epinephrine.

Refractory no-reflow is associated with adverse outcomes in patients undergoing percutaneous coronary intervention. Charts were reviewed to identify 29 consecutive patients in whom intracoronary epinephrine was administered for refractory no-reflow. The effects of intracoronary epinephrine on coronary flow (TIMI grade), cardiac rhythm, and systolic blood pressure in the cardiac catheterization laboratory were assessed. Administration of intracoronary epinephrine (mean dose, 139 +/- 189 microg) resulted in significant improvement in coronary flow. After administration, TIMI 3 flow was established in 69% of patients. Overall, TIMI flow significantly increased (mean TIMI flow form 1.0 +/- 1.0 to 2.66 +/- 0.55; P = 0.0001). Intracoronary epinephrine resulted in significant but tolerable increase in heart rate (72 +/- 19 to 86 +/- 26 beats/min; P = 0.009), but no cases of acute dysrhythmia. These findings indicate that intracoronary epinephrine may exert salutary effects in patients suffering refractory no-reflow following elective or acute coronary interventions.

Primary percutaneous interventions for acute myocardial infarction in octogenarians: a single-center experience.

BACKGROUND: The majority of cardiovascular deaths occur in the elderly. The safety and results of primary infarct intervention in octogenarians is not well characterized. HYPOTHESIS: The purpose of this study was to compare the results of primary infarct intervention in octogenarians with those in younger patients during 1997-1998 and to compare these results to those obtained in octogenarians treated in 1991-1994. METHODS: During 1997-1998, 40 octogenarians were treated with primary infarct intervention and were compared with 60 randomly selected patients aged < 80 years treated during the same time period. The results in octogenarians were compared with the results in a group of 37 patients of similar age treated in 1991-1994. The baseline characteristics, procedural results, and hospital outcome were obtained from a prospectively designed interventional database at a busy single-center program. RESULTS: There was no significant difference in hospital survival between the two groups of patients treated in 1997-1998 although there was a trend toward higher mortality in the octogenarian group. Length of stay and use of intra-aortic balloon pumps were greater in the octogenarian group. When the results in octogenarians treated in 1997-1998 were compared with the group of 37 patients treated in 1991-1994, the hospital mortality declined from 27 to 10% (p = 0.05). CONCLUSIONS: There has been improvement in hospital mortality over the past decade for patients aged > or = 80 years treated with primary infarct intervention. Hospital resources and length of stay are greater for the octogenarian group. Ongoing research studies are comparing the results of thrombolytic therapy and primary intervention in aged patients.