An association between collateral blood flow and myocardial viability in patients with recent myocardial infarction

BACKGROUND

We hypothesized that successful reperfusion of an occluded infarct-related coronary artery even late after acute myocardial infarction would result in improved regional wall motion and that such improvement might be related to the presence of collateral blood flow within the infarct bed.

METHODS

We assessed regional wall motion by two-dimensional echocardiography at base line and one month after angioplasty was attempted in the occluded infarct-related artery in 43 patients who had had a myocardial infarction two days to five weeks earlier. A wall-motion score was assigned to each patient on a five-point scale (from 1 [normal function] to 5 [dyskinesia]). The percentage of the infarct bed perfused by collateral flow was assessed with myocardial contrast echocardiography.

RESULTS

In the 41 patients who had abnormal wall motion at base line, improvement in function was noted in 25 (78 percent) of the 32 in whom angioplasty was successful, as compared with only 1 (11 percent) of the 9 in whom it was unsuccessful (P < 0.001). The percentage of the infarct bed supplied by collateral flow at base line was directly correlated with wall function and inversely correlated with the wall-motion score one month after successful angioplasty (r = -0.64, P < 0.001). Among the patients in whom angioplasty was successful, the 23 in whom > 50 percent of the infarct bed was supplied by collateral flow had better wall motion (P < 0.001) and greater improvement in wall motion at one month (P = 0.004) than the 9 in whom < or = 50 percent of the bed was supplied by collateral flow. The degree of improvement in function was not influenced by the length of time between the infarction and the attempted angioplasty.

CONCLUSIONS

The myocardium remains viable for a prolonged period in many patients with acute infarction and an occluded infarct-related artery. Viability appears to be associated with the presence of collateral blood flow within the infarct bed.

ACCF/ASE/AHA/ASNC/HFSA/HRS/SCAI/SCCM/SCCT/SCMR 2011 Appropriate Use Criteria for Echocardiography. A Report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, American Society of Echocardiography, American Heart Association, American Society of Nuclear Cardiology, Heart Failure Society of America, Heart Rhythm Society, Society for Cardiovascular Angiography and Interventions, Society of Critical Care Medicine, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance American College of Chest Physicians

The American College of Cardiology Foundation (ACCF), in partnership with the American Society of Echocardiography (ASE) and along with key specialty and subspecialty societies, conducted a review of common clinical scenarios where echocardiography is frequently considered. This document combines and updates the original transthoracic and transesophageal echocardiography appropriateness criteria published in 2007 (1) and the original stress echocardiography appropriateness criteria published in 2008 (2). This revision reflects new clinical data, reflects changes in test utilization patterns,and clarifies echocardiography use where omissions or lack of clarity existed in the original criteria.The indications (clinical scenarios)were derived from common applications or anticipated uses, as well as from current clinical practice guidelines and results of studies examining the implementation of the original appropriate use criteria (AUC).The 202 indications in this document were developed by a diverse writing group and scored by a separate independent technical panel on a scale of 1 to 9,to designate appropriate use(median 7 to 9), uncertain use(median 4 to 6), and inappropriate use (median 1 to 3). Ninety-seven indications were rated as appropriate, 34 were rated as uncertain, and 71 were rated as inappropriate. In general,the use of echocardiography for initial diagnosis when there is a change in clinical status or when the results of the echocardiogram are anticipated to change patient management were rated appropriate. Routine testing when there was no change in clinical status or when results of testing were unlikely to modify management were more likely to be inappropriate than appropriate/uncertain.The AUC for echocardiography have the potential to impact physician decision making,healthcare delivery, and reimbursement policy. Furthermore,recognition of uncertain clinical scenarios facilitates identification of areas that would benefit from future research.

Quantitative planar rest-redistribution 201Tl imaging in detection of myocardial viability and prediction of improvement in left ventricular function after coronary bypass surgery in patients with severely depressed left ventricular function

BACKGROUND

Although many patients with multivessel coronary artery disease (CAD) and severely depressed left ventricular (LV) function will benefit from coronary artery bypass graft surgery (CABG), surgeons may be reluctant to perform CABG on these patients without evidence of myocardial viability in regions of severe asynergy. We hypothesized that quantitative planar rest-redistribution 201Tl imaging would identify viable myocardium and predict improved regional and global function after revascularization in patients with depressed LV function and CAD.

METHODS AND RESULTS

Twenty-one patients (mean LV ejection fraction, 0.27 +/- 0.05) were studied. Regional and global LV functions were evaluated before and 8 weeks after CABG with radionuclide ventriculography. Segments were prospectively classified as showing normal, mildly reduced, or severely reduced viability on the basis of quantitative analysis of defect severity and redistribution on planar resting 201Tl imaging. By 201Tl criteria, 90% of hypokinetic segments were classified with normal or mildly reduced viability. Among akinetic or dyskinetic segments, 20% had normal 201Tl uptake, 53% had mildly reduced viability, and only 27% had severely reduced viability. 201Tl viability criteria identified segments that improved function after CABG. Sixty-two percent of severely asynergic segments with normal viability and 54% with mildly reduced viability improved function after surgery, but only 23% with severely reduced viability improved function (p = 0.002). When only adequately revascularized segments were considered, the predictive value of a positive preoperative viability scan for functional improvement was 73%. The greatest improvement in global LV function after CABG occurred in patients with the greatest number of asynergic segments classified as viable before surgery (p < 0.01). In 10 patients with more than seven viable, asynergic segments, mean LV ejection fraction increased significantly after CABG (0.29 +/- 0.07 to 0.41 +/- 0.11, p = 0.002). In 11 patients with seven or fewer viable, asynergic segments, mean LV ejection fraction remained unchanged after revascularization (0.27 +/- 0.05 to 0.30 +/- 0.08, p = NS).

CONCLUSIONS

In patients with CAD and severely depressed LV function, preoperative quantitative planar rest-redistribution. 201Tl imaging identifies viability in many asynergic myocardial segments, and these segments frequently improve function after CABG. The presence of numerous asynergic but viable myocardial segments before surgery correlated significantly with improvement in global LV function after bypass surgery.

Incremental value of combined perfusion and function over perfusion alone by gated SPECT myocardial perfusion imaging for detection of severe three-vessel coronary artery disease

OBJECTIVES

We hypothesized that combining functional assessment to perfusion enhances the ability of electrocardiographic gating Tc-99m sestamibi single photon emission computed tomography (gated SPECT) myocardial perfusion imaging (MPI) to detect defects in multiple vascular territories in patients with severe three-vessel coronary artery disease (3VD).

BACKGROUND

In patients with 3VD, perfusion defects in multiple vascular territories may not always be evident due to globally reduced perfusion.

METHODS

Gated SPECT MPIs were interpreted sequentially with perfusion first, followed by combined perfusion/function, in 143 patients with angiographic 3VD and a control group of 112 non-3VD patients. All patients underwent coronary arteriography within one month of MPI.

RESULTS

In 3VD patients, combined perfusion/function analysis yielded significantly greater numbers of abnormal segments/patient (6.2 +/- 4.7 vs. 4.1 +/- 2.8, p < 0.001) and more defects in multiple vascular territories (60% vs. 46%, p < 0.05) than perfusion alone. In the control group, there were no differences between the combined perfusion/function and perfusion alone interpretations. Multivariate analysis of 15 different clinical, stress, and scintigraphic variables in all patients revealed age (p < 0.0001) and number of abnormal vascular territories by combined perfusion/function (p < 0.0001) to be the most powerful predictors of 3VD. Addition of functional data to clinical, stress, and perfusion yielded a significant increase in the predictive value of 3VD (global chi-square: 131.7 vs. 89.8, p < 0.00001). Specificity of combined perfusion/function analysis was not lower than perfusion alone (72% vs. 69%, p = NS). CONCLUSIONS; Adjunctive assessment of function with perfusion by gated SPECT MPI enhances the detection of defects in multiple vascular territories in patients with severe 3VD, without adversely affecting its specificity.

Improved outcome after coronary bypass surgery in patients with ischemic cardiomyopathy and residual myocardial viability

BACKGROUND

Although residual myocardial viability in patients with coronary artery disease and extensive regional asynergy is associated with improved ventricular function after coronary bypass surgery, the relationship between viability and clinical outcome after surgery is unclear. We hypothesized that patients with poor ventricular function and predominantly viable myocardium have a better outcome after bypass surgery compared with those with less viability.

METHODS AND RESULTS

Seventy patients with multivessel coronary artery disease and left ventricular ejection fractions < 40% who underwent preoperative quantitative 201Tl scintigraphy before coronary bypass surgery were analyzed retrospectively. 201Tl scintigrams were reviewed blindly, and each segment was assigned a score based on defect magnitude. Segmental viability scores were summed and divided by the number of segments visualized to determine a viability index. The viability index was significantly related to 3-year survival free of cardiac event (cardiac death or heart transplant) after bypass surgery (P=.011) and was independent of age, ejection fraction, and number of diseased coronary vessels. Patients with greater viability (group 1; viability index > 0.67; n=33) were similar to patients with less viability (group 2; viability index < or = 0.67; n=37) with respect to age, comorbidities, and extent of coronary artery disease. There were 6 cardiac deaths and no heart transplants in group 1 patients and 15 cardiac deaths and two transplants in group 2 patients. Survival free of cardiac death or transplantation was significantly better in group 1 patients on Kaplan-Meier analysis (P=.018).

CONCLUSIONS

We conclude that resting 201Tl scintigraphy may be useful in preoperative risk stratification for identification of patients more likely to benefit from surgical revascularization.

Microvascular integrity indicates myocellular viability in patients with recent myocardial infarction. New insights using myocardial contrast echocardiography

BACKGROUND

Patency of the infarct-related artery (IRA) after acute myocardial infarction (AMI) may not reflect the magnitude of tissue perfusion. In animal models of AMI, myocardial cellular necrosis has been associated with extensive capillary damage. Because myocardial contrast echocardiography (MCE) can define the spatial distribution of microvascular perfusion, we hypothesized that it could be used in patients after recent AMI to distinguish myocardial regions that have an intact microvasculature and thus are viable from those without an intact microvasculature and thus are not viable.

METHODS AND RESULTS

One hundred five patients with a recent AMI (range, 1 day to 4 weeks; median, 8 days) who were undergoing cardiac catheterization were included in the study. Two-dimensional echocardiography was performed at baseline and repeated 1 month later to assess regional function within the infarct zone (scores of 1 to 5 indicating normal to dyskinetic segments, respectively). MCE was performed in the cardiac catheterization laboratory to assess microvascular perfusion within the infarct bed. A contrast score index was derived by assigning scores to individual segments within the infarct zone (0, 0.5, and 1 denoting no, intermediate, and homogeneous contrast effect, respectively) and deriving the average score within the infarct bed. Revascularization was performed as clinically indicated. Although the baseline wall motion score and the contrast score index were similar in the 90 patients with a patent IRA and the 15 patients with an occluded IRA (median +/- 1 interquartile range, 3 +/- 1 versus 3.5 +/- 1; P = .41), wall motion score 1 month later was significantly better in those with open IRAs compared with those with closed IRAs (2 +/- 2 versus 3 +/- 2, P = .05). In the 90 patients with an open IRA, a strong correlation was noted between wall motion score 1 month later and the contrast score index (rho = -.64, P < .001). On multivariate analysis, the best correlate of the 1-month wall motion score was the contrast score index.

CONCLUSIONS

In patients studied in the cardiac catheterization laboratory between 1 day and 4 weeks after AMI, an intact microvasculature as identified by MCE indicates myocardial regions that improve function 1 month later. This study demonstrates that microvascular patency is closely associated with myocardial cellular viability after AMI in humans.

Noninvasive quantification of coronary blood flow reserve in humans using myocardial contrast echocardiography

BACKGROUND

We hypothesized that coronary blood flow (CBF) reserve could be quantified noninvasively in humans using myocardial contrast echocardiography (MCE).

METHODS AND RESULTS

Eleven patients with normal epicardial coronary arteries (group I) and 19 with single-vessel coronary stenosis (group II) underwent quantitative coronary angiography, MCE, and CBF velocity measurements at rest and during intravenous adenosine infusion. In group I patients, MCE-derived myocardial blood flow (MBF) velocity reserve (2.4+/-0.08) was similar to CBF velocity reserve using a Doppler flow wire (2.4+/-1.1). Patients with a single risk factor had a significantly higher MBF reserve (3.0+/-0.89) than those with >/=2 risk factors (1.7+/-0.22). In group II patients, significant differences were found in MBF velocity reserve in patients with mild (<50%), moderate (50% to 75%), or severe (>75%) stenoses (2.2+/-0.40, 1.6+/-0.65, and 0.55+/-0.19, respectively; P=0.005). A linear relation was found between flow velocity reserve determined using the 2 methods (r=0.76, P<0.001), and a curvilinear relation was noted between the percent coronary stenosis measured using quantitative coronary angiography and velocity reserve using both methods.

CONCLUSIONS

CBF reserve can be measured in humans using MCE. This method may allow the noninvasive assessment of coronary stenosis severity and the detection of microvascular dysfunction.

Functional significance of collateral blood flow in patients with recent acute myocardial infarction. A study using myocardial contrast echocardiography

BACKGROUND

We hypothesized that myocardial contrast echocardiography (MCE) can be used to both measure collateral blood flow as well as assess the functional significance of collaterals in patients with acute myocardial infarction (AMI).

METHODS AND RESULTS

MCE was performed in 33 patients with recent AMI (12 +/- 7 days) and an occluded infarct-related artery (IRA), both before and after attempted percutaneous transluminal coronary angioplasty (PTCA). The size of the occluded bed was defined in patients with successful PTCA by injecting contrast directly into the opened IRA and expressed as a percent of the myocardium in the short-axis view. The percent of the perfusion bed supplied by collaterals before PTCA was determined. Transit rates of the microbubbles within the collateralized regions were also measured and were expressed as a percent of the transit rates in the normal adjacent beds. Regional function within the occluded bed was assessed using echocardiography and was graded as 1 (normal) to 5 (dyskinetic). Collaterals were graded on coronary angiography as 0 (none) to 3 (abundant). The perfusion bed size was larger for the left anterior descending (LAD) than for the right (RCA) and left circumflex (LCx) coronary arteries (37 +/- 6% versus 27 +/- 12% of the myocardium, p = 0.02). The percent of the occluded bed supplied by collateral flow was greater for RCA and LCx compared with the LAD (87 +/- 30% versus 72 +/- 22%, p less than 0.01). There was poor correlation between MCE-defined percent of occluded bed supplied by collaterals and angiographic collateral grade (r = 0.13). Regions supplied by collaterals were less likely to show confluent hypoperfused zones after reperfusion compared with those not supplied by collaterals. Similarly, the percent of myocardium not perfused by either anterograde or collateral flow correlated well (r = 0.67, p less than 0.01) with peak creatine kinase levels and was more likely to be associated with Q waves. Finally, although there was poor correlation between angiographic collaterals and regional function (r = 0.20), there was a significant negative correlation between MCE-defined spatial extent of collateral flow and regional function (r = -0.57, p less than 0.01).

CONCLUSION

MCE can be used to measure collateral flow in patients with recent AMI and to assess the functional significance of collaterals in these patients. This technique may be ideally suited for the assessment of collateral perfusion in patients undergoing cardiac catheterization.

Comparison between visual assessment and quantitative angiography versus fractional flow reserve for native coronary narrowings of moderate severity

We tested the hypothesis that experienced interventional cardiologists can identify patients with fractional flow reserve (FFR) <0.75 either by visual assessment of the angiogram or by quantitative coronary angiography (QCA). Estimation of the significance of moderate lesions is difficult. FFR can determine the physiologic significance of a stenosis. Data comparing visual assessment and QCA of moderate lesions with FFR are limited. FFR was measured in 83 moderate lesions defined as having a 40% to 70% stenosis by visual inspection. An FFR <0.75 was considered "significant." Lesions were visually assessed by 3 experienced interventional cardiologists and their significance estimated. QCA was performed. Both analyses were compared with FFR. FFR averaged 0.82 +/- 0.11 and was <0.75 in 15 of 83 lesions (18%). The reviewers' classification was concordant with the FFR in about half the lesions. Concordance between reviewers was poor (Spearman's rho = 0.36). Visual assessment resulted in good sensitivity (80%) and negative predictive value (91%), but poor specificity (47%) and positive predictive value (25%) compared with FFR. By QCA, no patient with stenosis <60% or minimal luminal diameter >1.4 mm had FFR <0.75. QCA did not discriminate the significance of lesions outside of these parameters. Thus, neither visual assessment of an angiogram by experienced interventional cardiologists nor QCA can accurately predict the significance of most moderate narrowings.

Comparison between angiography and fractional flow reserve versus single-photon emission computed tomographic myocardial perfusion imaging for determining lesion significance in patients with multivessel coronary disease

We hypothesized that myocardial perfusion imaging (MPI) would fail to identify all vascular zones with the potential for myocardial ischemia in patients with multivessel coronary disease (MVD). MPI is based on the concept of relative flow reserve. The ability of these techniques to determine the significance of a particular stenosis in the setting of MVD is questionable. Fractional flow reserve (FFR) can determine the significance of individual stenoses. Thirty-six patients with disease involving 88 arteries underwent angiography, FFR, and MPI. FFR was performed using a pressure wire with hyperemia from intracoronary adenosine. Myocardial perfusion images were analyzed quantitatively and segments assigned to a specific coronary artery. The relation between FFR and perfusion was determined for each vascular zone. Of the 88 vessels, the artery was occluded (n=20) or had an abnormal FFR<or=0.75 (n=34) in 54 of 88 (61%). MPI showed no defect in 51 zones (58%). Concordance between angiography, FFR, and MPI was seen in 61 of 88 zones (69%). Discordance was seen in the remaining 27 zones (31%) and was predominantly from the finding of a FFR<0.75 or total occlusion despite no defect on MPI. In conclusion, many patients with MVD show no perfusion defect in zones supplied by arteries with total occlusion or a FFR<0.75. Thus, MPI underestimates ischemic burden and FFR may be better at guiding revascularization decisions than perfusion imaging in patients with MVD.

Prevalence of unfavorable angiographic characteristics for percutaneous intervention in patients with unprotected left main coronary artery disease

OBJECTIVES

The goal of this study was to determine the proportion of patients with left main coronary disease (LMCD) with unfavorable characteristics for percutaneous coronary intervention (PCI).

BACKGROUND

Published series suggest that LMCD can be treated percutaneously, however, the proportion of patients in whom PCI is an option based on angiographic criteria is unknown.

METHODS

In 13,228 consecutive coronary angiograms, 476 (3.6%) patients had < or =60% stenosis of the left main. In 232 patients with unprotected LMCD, the clinical characteristics and angiograms were reviewed with six features chosen as "unfavorable" for PCI: (1) Bifurcation LMCD, (2) occlusion of a major coronary, (3) ejection fraction <30%, (4) occlusion of a dominant RCA, (5) left dominant circulation, and (6) coexisting three-vessel disease. Treatment modality and 1 year mortality were determined.

RESULTS

The mean age was 69 years and 68% were male. Unfavorable characteristics were common with at least one unfavorable characteristic seen in 80%. Bifurcation disease was the most common unfavorable characteristic observed (53%) and coexisting three-vessel disease was seen in 38%. Treatment consisted of CABG in 205 (88%), medical therapy in 24 (10%) and PCI in 3 (1%). Among patients referred for CABG, 1 year survival was 88% with similar rates of survival for those with favorable characteristics (86%) compared to those with at least one unfavorable characteristic (88%).

CONCLUSIONS

Most patients with LMCD have at least one unfavorable characteristic for PCI suggesting that PCI may be a technically difficult option for most patients with LMCD.

Detection of myocardial viability by contrast echocardiography in acute infarction predicts recovery of resting function and contractile reserve

OBJECTIVES

We sought to determine whether myocardial contrast echocardiography (MCE) performed before and early after primary coronary stenting (PCS) in patients with acute myocardial infarction (AMI) could predict recovery of resting left ventricular systolic function and contractile reserve.

BACKGROUND

Myocardial contrast echocardiography can be used to assess perfusion within the risk area before PCS and the extent of necrosis soon after PCS.

METHODS

In 30 patients with AMI, MCE and two-dimensional echocardiography were performed before PCS and 3 to 5 days and 4 weeks after PCS. Contractile reserve was assessed by dobutamine echocardiography at four weeks in patients with persistent severe wall-motion abnormalities.

RESULTS

Of segments without perfusion at 3 to 5 days, 95% had severe hypokinesis to akinesis at 4 weeks. Of segments with normal perfusion at 3 to 5 days, 90% had normal wall motion or mild hypokinesis at 4 weeks, whereas those with partial perfusion at 3 to 5 days were evenly divided between normal wall motion, hypokinesis, and akinesis. In segments with persistent severe wall-motion abnormalities at four weeks, contractile reserve was found in >80% of segments with perfusion, compared with only 10% of segments without detectable perfusion (p < 0.01). The presence of myocardial perfusion by MCE before PCS was associated with maintained or improved perfusion at 3 to 5 days and eventual recovery of resting wall motion.

CONCLUSIONS

Myocardial contrast echocardiography performed early after PCS provides information on the extent of infarction, and hence the likelihood for recovery of resting systolic function or contractile reserve. The presence of perfusion before PCS, from either collateral or antegrade flow, predicts the maintenance of perfusion and recovery of systolic function.

Coronary flow reserve abnormalities in patients with diabetes mellitus who have end-stage renal disease and normal epicardial coronary arteries

BACKGROUND

Diabetic nephropathy is associated with increased cardiovascular events. Coronary atherosclerosis is responsible for many of these events, but other mechanisms such as impaired flow reserve may be involved. The purpose of this study was to define the prevalence and mechanism of abnormal coronary velocity reserve (CVR) in patients with diabetes mellitus who have nephropathy and a normal coronary artery.

METHODS

Patients undergoing catheterization for clinical purposes were enrolled. CVR was measured with a Doppler ultrasound scanning wire in a normal coronary in 32 patients without diabetes mellitus, 11 patients with diabetes mellitus who did not have renal failure, and 21 patients with diabetes mellitus who had nephropathy. A CVR <2.0 was considered to be abnormal.

RESULTS

Patients with diabetes mellitus who had renal failure had a higher incidence of hypertension and left ventricular hypertrophy. The average peak velocity (APV) at baseline was higher in patients with diabetes mellitus who had renal failure. At peak hyperemia, APV increased in all 3 groups, with no difference between groups. The mean CVR for patients without diabetes was 2.8 +/- 0.8 and was not different from that in patients with diabetes mellitus who did not have renal failure (2.7 +/- 0.7), but was lower than that in patients with diabetes mellitus who had renal failure (1.6 +/- 0.5; P < 0.001). Abnormal CVR was observed in 9% of patients without diabetes mellitus, 18% of patients with diabetes mellitus who did not have renal failure, and 57% of patients with diabetes mellitus who had renal failure, and abnormal CVR was caused by an elevation of baseline APV in 66% of these cases. The baseline heart rate and the presence of diabetes mellitus with renal failure were independent predictors of abnormal CVR by multivariable analysis.

CONCLUSIONS

Patients with diabetic nephropathy have abnormalities in CVR in the absence of angiographically evident coronary disease.

Specific factor Xa inhibition reduces restenosis after balloon angioplasty of atherosclerotic femoral arteries in rabbits

BACKGROUND

Balloon angioplasty of atherosclerotic arteries results in activation of the coagulation cascade. Several coagulation factors, including factor Xa and thrombin, are mitogenic for vascular smooth muscle cells in vitro and thus may play a role in restenosis after balloon angioplasty. Specific inhibition of factor Xa can be achieved with recombinant antistasin (rATS) or tick anticoagulant peptide (rTAP). We hypothesized that inhibition of Xa would limit restenosis after balloon angioplasty in an atherosclerotic rabbit model.

METHODS AND RESULTS

Focal femoral atherosclerosis was induced by air desiccation injury and a high-cholesterol diet in 38 New Zealand White rabbits. Recombinant antistasin (n = 20 arteries) or rTAP (n = 14 arteries) was administered by intravenous bolus at the time of balloon angioplasty and followed by a 2-hour infusion; controls (n = 21 arteries) received bolus heparin alone (150 U/kg). Therapeutic prolongation of the activated partial thromboplastin time occurred, and antithrombotic drug levels were achieved in all animals. Luminal diameter in millimeters by quantitative angiography did not differ between treatment groups before (1.1 +/- 0.2 for controls, 1.1 +/- 0.2 for rATS, and 1.1 +/- 0.3 for rTAP) or after balloon angioplasty (1.5 +/- 0.3 for controls, 1.4 +/- 0.2 for rATS, and 1.4 +/- 0.2 for rTAP). At 28 days, treatment with factor Xa inhibitors tended to result in arteries with larger luminal diameter than controls (1.2 +/- 0.3 for rATS, 1.2 +/- 0.3 for rTAP versus 1.0 +/- 0.3 for control, P = .09 by one-way ANOVA). Restenosis, defined as reduction in angiographic luminal diameter (in mm) from 2 hours after angioplasty to 28 days after angioplasty was less in the rATS group than in controls (-0.2 +/- 0.1 versus -0.5 +/- 0.4, P < .001) and tended to be less in the rTAP group (-0.3 +/- 0.2 versus -0.5 +/- 0.4, P = .07). Quantitative histopathological analysis showed less percent cross-sectional area narrowing by plaque in both rATS- and rTAP-treated arteries compared with controls (42 +/- 21%, 47 +/- 18%, and 63 +/- 14%, respectively; P < .01 by one-way ANOVA).

CONCLUSIONS

We conclude that a 2-hour infusion of rATS or rTAP reduced angiographic restenosis and resulted in less luminal cross-sectional narrowing by plaque compared with controls.

ACCF/SCAI/STS/AATS/AHA/ASNC/HFSA/SCCT 2012 appropriate use criteria for coronary revascularization focused update: a report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, Society for Cardiovascular Angiography and Interventions, Society of Thoracic Surgeons, American Association for Thoracic Surgery, American Heart Association, American Society of Nuclear Cardiology, and the Society of Cardiovascular Computed Tomography

The American College of Cardiology Foundation (ACCF), Society for Cardiovascular Angiography and Interventions, Society of Thoracic Surgeons, and the American Association for Thoracic Surgery, along with key specialty and subspecialty societies, conducted an update of the appropriate use criteria (AUC) for coronary revascularization frequently considered. In the initial document, 180 clinical scenarios were developed to mimic patient presentations encountered in everyday practice and included information on symptom status, extent of medical therapy, risk level as assessed by noninvasive testing, and coronary anatomy. This update provides a reassessment of clinical scenarios the writing group felt to be affected by significant changes in the medical literature or gaps from prior criteria. The methodology used in this update is similar to the initial document, and the definition of appropriateness was unchanged. The technical panel scored the clinical scenarios on a scale of 1 to 9. Scores of 7 to 9 indicate that revascularization is considered appropriate and likely to improve patients' health outcomes or survival. Scores of 1 to 3 indicate revascularization is considered inappropriate and unlikely to improve health outcomes or survival. Scores in the mid-range (4 to 6) indicate a clinical scenario for which the likelihood that coronary revascularization will improve health outcomes or survival is uncertain. In general, as seen with the prior AUC, the use of coronary revascularization for patients with acute coronary syndromes and combinations of significant symptoms and/or ischemia is appropriate. In contrast, revascularization of asymptomatic patients or patients with low-risk findings on noninvasive testing and minimal medical therapy are viewed less favorably. The technical panel felt that based on recent studies, coronary artery bypass grafting remains an appropriate method of revascularization for patients with high burden of coronary artery disease (CAD). Additionally, percutaneous coronary intervention may have a role in revascularization of patients with high burden of CAD. The primary objective of the appropriate use criteria is to improve physician decision making and patient education regarding expected benefits from revascularization and to guide future research.

Usefulness of Psoas Muscle Area to Predict Mortality in Patients Undergoing Transcatheter Aortic Valve Replacement

Frailty has become high-priority theme in cardiovascular diseases because of aging and increasingly complex nature of patients. Low muscle mass is characteristic of frailty, in which invasive interventions are avoided if possible because of decreased physiological reserve. This study aimed to determine if the psoas muscle area (PMA) could predict mortality and to investigate its utility in patients who underwent transcatheter aortic valve replacement (TAVR). We retrospectively reviewed 232 consecutive patients who underwent TAVR. Cross-sectional areas of the psoas muscles at the level of fourth lumbar vertebra were measured by computed tomography and normalized to body surface area. Patients were divided into tertiles according to the normalized PMA for each gender (men: tertile 1, 1,708 to 1,178 mm(2)/m(2); tertile 2, 1,176 to 1,011 mm(2)/m(2); and tertile 3, 1,009 to 587 mm(2)/m(2); women: tertile 1, 1,436 to 962 mm(2)/m(2); tertile 2, 952 to 807 mm(2)/m(2); and tertile 3, 806 to 527 mm(2)/m(2)). Smaller normalized PMA was independently correlated with women and higher New York Heart Association classification. After adjustment for multiple confounding factors, the normalized PMA tertile was independently associated with mortality at 6 months (adjusted hazard ratio 1.53, 95% confidence interval 1.06 to 2.21). Kaplan-Meier analysis showed that tertile 3 had higher mortality rates than tertile 1 at 6 months (14% and 31%, respectively, p = 0.029). Receiver-operating characteristic analysis showed that normalized PMA provided the increase of C-statistics for predicting mortality for a clinical model and gait speed. In conclusion, PMA is an independent predictor of mortality after TAVR and can complement a clinical model and gait speed.

Thrombin and vascular smooth muscle cell proliferation: implications for atherosclerosis and restenosis

Despite long-standing knowledge about the relationship between thrombosis and atherosclerosis, the specific role of thrombin in modulating atherosclerosis and the response to vascular injury is not well understood. Thrombin receptor stimulation in vitro signals many cellular events that are associated with the response to vascular injury (atherosclerosis) in vivo. Proliferation of smooth muscle cells (SMCs) is an important component of the response to vascular injury. We have previously shown that human alpha-thrombin and the 14-amino acid human thrombin receptor-activating peptide (huTRAP-14) stimulate proliferation of cultured rat aortic SMCs. However, thrombin-induced SMC proliferation demonstrates delayed kinetics relative to platelet-derived growth factor (PDGF-BB, another potent SMC mitogen). Several mechanisms may be responsible for these delayed kinetics in vitro, including production of necessary secondary growth factors and thrombin-induced upregulation of its receptor. In vivo studies have demonstrated that thrombin inhibition limits the response to vascular injury in a hypercholesterolemic rabbit model of focal femoral atherosclerosis. However, this effect does not appear to be mediated by effects on early SMC proliferation. In this discussion, we will address the mechanisms of thrombin-induced SMC proliferation in vitro and apply this knowledge to our understanding of the role of thrombin inhibition in limiting the response to vascular injury in vivo.

Efficacy and safety of ventricular tachycardia ablation with mechanical circulatory support compared with substrate-based ablation techniques

AIMS

Catheter ablation of ventricular tachycardia (VT) can be limited by haemodynamic instability. In these cases, substrate-based ablation is typically performed. An alternative is to perform activation and entrainment mapping during VT supported by a percutaneous left ventricular assist device (pVAD). We sought to compare the complication and success rates of pVAD-assisted VT ablation with scar-based techniques.

METHODS AND RESULTS

Thirteen consecutive patients with haemodynamically unstable VT underwent pVAD-assisted ablation (pVAD group) and were retrospectively compared with 18-matched patients undergoing a substrate-based VT ablation (non-pVAD group). There was no significant difference in age or ejection fraction between the groups although pVAD patients tended to have more shocks in the preceding months. Procedure times were longer for the pVAD group. The number of monomorphic VTs induced was greater in the pVAD group (3.2 vs. 1.6, P= 0.04); however, after ablation, there was no difference in inducibility between the pVAD and non-pVAD group (10 of 13 vs. 12 of 18; 77 vs. 67%, P = 0.69). There was no difference in acute complications including stroke or death. At 9 ± 3 months, 1-year freedom from implantable cardioverter-defibrillator (ICD) shocks/therapies for sustained VT were similar (P= 0.96). In multivariable analysis, the absence of atrial fibrillation (hazard ratio=0.15, P= 0.04) was associated with a lower incidence of ICD shocks.

CONCLUSIONS

In high-risk patients, pVAD-assisted VT ablation guided by activation and entrainment mapping is a feasible alternative to substrate mapping and allows outcomes comparable to substrate mapping.

Efficacy and safety of intensive antiplatelet therapy with prasugrel from TRITON-TIMI 38 in a core clinical cohort defined by worldwide regulatory agencies

TRITON-TIMI 38 showed that in patients with acute coronary syndrome undergoing percutaneous coronary intervention prasugrel decreased ischemic events compared to standard clopidogrel, but with more bleeding. The United States Food and Drug Administration and the European Medicines Agency approved prasugrel but provided contraindications in patients with previous stroke or transient ischemic attack and recommended limited use or reduced dose in patients ≥75 years old and weighing <60 kg. This defined 3 clinically relevant groups of patients for use of prasugrel at the studied dose regimen: group I (core clinical cohort), group II (noncore cohort), and group III (contraindicated). We assessed clinical outcomes of patients within these cohorts in the TRITON-TIMI 38 trial. Survival analysis methods were used to compare outcomes by treatment assignment (prasugrel vs clopidogrel) and by cohort (groups I and II or III). Patients in group I (n = 10,804, 79%) treated with prasugrel had a clinically significant and robust decrease in the primary end point of cardiovascular death, myocardial infarction, or stroke (8.3 vs 11.0%, hazard ratio [HR] 0.74, 95% confidence interval 0.66 to 0.84, p <0.0001), whereas patients in group II (n = 2149, 16%) had limited efficacy (15.3% vs 16.3%, HR 0.94, 0.76 to 1.18, p = 0.61, p for interaction = 0.07). For Thrombolysis In Myocardial Infarction major bleeding not related to coronary artery bypass grafting, there were tendencies to higher rates with prasugrel in group I (1.9% vs 1.5%, HR 1.24, 0.91 to 1.69, p = 0.17) and group II (4.1% vs 3.4%, HR 1.23, 0.77 to 1.97, p = 0.40); however, the absolute difference was greater for group II. The net clinical outcome (all-cause death/myocardial infarction/stroke/Thrombolysis In Myocardial Infarction major bleeding) in group I patients was highly favorable (10.2% vs 12.5%, HR 0.80, 0.71 to 0.89, p <0.0001) and neutral in group II (19.5% vs 19.7%, HR 0.98, 0.81 to 1.20, p for interaction = 0.07). Patients in group III (n = 518, 4%) did poorly with regard to efficacy and safety. In TRITON-TIMI 38 patients without previous stroke, <75 years old, and weighing >60 kg had substantial decreases in ischemic events with prasugrel compared to clopidogrel. Although relative bleeding excess exists in this population, absolute rates and differences in bleeding were attenuated. In conclusion, these data indicate that use of prasugrel in a core clinical cohort that has been defined by regulatory action will maximize the benefit of prasugrel and limit the risk of adverse outcomes.

All-trans-retinoic acid limits restenosis after balloon angioplasty in the focally atherosclerotic rabbit : a favorable effect on vessel remodeling

All-trans-retinoic acid (atRA) has potent in vitro effects on a number of processes involved in vascular injury and repair, such as modulating smooth muscle cell (SMC) proliferation and inducing SMC differentiation, and may play an important role in the in vivo response to vascular injury. We hypothesized that atRA would limit restenosis after balloon angioplasty through SMC-modulated changes in plaque size and vessel geometry. Balloon angioplasty was performed on rabbits with focal femoral atherosclerosis randomized to treatment with atRA or saline. At 28 days after balloon angioplasty, minimal luminal diameter was significantly larger in the atRA group (1.24+/-0.17 versus 1.12+/-0.22 mm, P=0.02). Histomorphometry confirmed a larger lumen area (0.51+/-0.20 versus 0. 34+/-0.13 mm(2), P=0.004) in the atRA group, with no difference in absolute plaque area. Internal elastic lamina and external elastic lamina areas were significantly larger in the atRA group (0.89+/-0. 27 versus 0.66+/-0.24 mm(2), P=0.001, and 1.29+/-0.38 versus 0. 98+/-0.32 mm(2), P=0.001, respectively). Vessel sections exhibited significantly more alpha-actin and desmin immunostaining (P=0.01) in the atRA-treated group. No differences in early cellular proliferation and collagen content were detected with the use of bromodeoxyuridine. In this atherosclerotic model of vascular injury, atRA limits restenosis after balloon angioplasty by effects secondary to overall vessel segment enlargement at the angioplasty site rather than by effects on plaque size or cellular proliferation. Increased alpha-actin and desmin immunostaining suggest a possible role for phenotypic modulation of SMCs in this favorable remodeling effect.

Identification of viable myocardium with contrast echocardiography in patients with poor left ventricular systolic function caused by recent or remote myocardial infarction

We hypothesized that viable myocardium can be identified in patients with poor left ventricular (LV) systolic function caused by recent or prior infarction using myocardial contrast echocardiography. Accordingly, 39 patients with reduced LV ejection fraction (range 0.10 to 0.40) and recent (n = 30) or remote (n = 9) myocardial infarction were studied. Echocardiography was performed at baseline and at 1 month to assess regional function (1 = normal, 5 = dyskinesia) in 12 segments/patient; the segments were also scored for contrast effect (1 = homogenous, 0.5 = partial, 0 = none) during contrast echocardiography performed in the cardiac catheterization laboratory. Four patients had unsuccessful angioplasty of occluded arteries and were treated medically, 9 were treated medically because of noncritical coronary stenoses (< 80%), and 26 underwent revascularization (16 angioplasty and 10 bypass operation). Twelve segments could not be visualized (2 each in 6 patients), and 30 segments continued to be subserved by totally occluded arteries because of unsuccessful angioplasty in 4 patients. Of the remaining 426 segments, 186 (44%) demonstrated baseline wall motion scores of > or = 3. The best correlate of 1-month wall motion score in these segments was the contrast score (p = -0.62), with better 1-month function noted in segments with more contrast. The overall perfusion status of LV myocardium also correlated (p = -0.59) with global LV systolic function at 1 month. We conclude that myocardial contrast echocardiography can be used during cardiac catheterization to define myocardial segments that are viable in patients with poor LV systolic function caused by recent or remote myocardial infarction.