Relation of phasic coronary flow velocity characteristics with TIMI perfusion grade and myocardial recovery after primary percutaneous transluminal coronary angioplasty and rescue stenting

Evaluating the role of intravenous pentoxifylline administration on primary percutaneous coronary intervention success rate in patients with ST-elevation myocardial infarction (PENTOS-PCI)

Ischemia reperfusion injury can lead to further myocardiocyte damage in patients with ST-elevation myocardial infarction (STEMI). Pentoxifylline is a methylxanthine derivative with known anti-inflammatory, antioxidant, vasodilator, and rheological properties which can be a promising agent in preventing reperfusion injury. PENTOS-PCI is a single-center, randomized, double-blind, placebo-controlled trial which evaluated the efficacy and safety of preprocedural administration of intravenous pentoxifylline in patients undergoing primary percutaneous coronary intervention (PCI). Patients with acute STEMI who were eligible for PCI were randomized to receive either 100-mg intravenous infusion of pentoxifylline or placebo, prior to transferring to catheterization laboratory. Overall, 161 patients were included in our study of whom 80 patients were assigned to pentoxifylline and 81 to the control groups. Per-protocol analysis of primary endpoint indexing PCI's success rate as measured by thrombolysis in myocardial infarction (TIMI) flow grade 3 was not significantly different between pentoxifylline and placebo (71.3% and 66.3% respectively, P = 0.40). In addition, pentoxifylline could not improve secondary angiographic endpoints including myocardial blush grade 3 (87.5% and 85.2%, P = 0.79) and corrected TIMI frame count (22.8 [± 9.0] and 24.0 [± 5.1], P = 0.33) in the intervention and placebo groups respectively. The rates of major adverse cardiac and treatment emergent adverse effects were not significantly different between the two groups. Administration of intravenous pentoxifylline before primary PCI did not improve the success rate of the procedure in patients with STEMI. Intravenous administration of pentoxifylline was well tolerated, and there were no significant differences regarding adverse drug reactions in the two groups. Panel A, background: pentoxifylline is a methylxanthine derivative with known anti-inflammatory, antioxidant, vasodilator, and rheological properties which can be a promising agent in preventing reperfusion injury. Panel B: study design and main results of the PENTOS-PCI trial. cTFC corrected TIMI frame count, ED emergency department, IRI ischemia reperfusion injury, MBG myocardial blush grade, PCI percutaneous coronary intervention, PPCI primary PCI, PTX pentoxifylline, ROS reactive oxygen species, SD standard deviation, STEMI ST-elevation myocardial infarction, TIMI thrombolysis in myocardial infarction.

Utility of angiography-physiology coregistration maps during percutaneous coronary intervention in clinical practice

This study aimed to evaluate the utility and feasibility of physiological maps coregistered with angiograms using the pullback of a pressure guidewire with continuous instantaneous wave-free ratio (iFR) measurements. iFR pullback was obtained for 70 lesions from 70 patients with stable angina pectoris using SyncVision (Philips Corp.). Physiological maps were created, whereby the post-intervention iFR (post-iFR) was predicted as iFRpred. The iFR gap was defined if the difference between the iFRpred and post-iFR was ≥ 0.3. The lesion morphology changed from that during the physiological assessment to that during the angiographic assessment in 26 lesions (37.1%). In particular, 22.6% of angiographic tandem lesions changed to physiological focal lesions. The mean pre-intervention iFR, post-iFR, and iFRpred were 0.73 ± 0.17, 0.90 ± 0.06, and 0.93 ± 0.05, respectively. The mean difference between the iFRpred and post-iFR was 0.029 ± 0.099, with 95% limits of agreement of -0.070-0.128. iFR gaps occurred in 28 patients (40%). Notably, a new iFR gradient causing a ≥ 0.03 iFR drop after stenting occurred in 11 (15.7%) cases. The study patients were divided into two groups according to biases between post-iFR and iFRpred < 0.03 (good concordance group) or ≥ 0.03 (poor concordance group). The pre-intervention heart rate was the only independent predictor of poor concordance (odds ratio, 0.936; 95% confidence interval 0.883-0.992; p = 0.027). Physiological maps under resting conditions may contribute to a reduction in unnecessary stent placements without missing lesions requiring treatment. However, the predictive accuracy of post-iFR performance in the present study was slightly lower than that in the previous reports.

Atrial Fibrillation is Associated with Femoropopliteal Totally Occlusive In-Stent Restenosis: A Single-Center, Retrospective, Observational Study

Introduction

The proportion of patients with comorbid atrial fibrillation (AF) and peripheral artery disease (PAD) has increased in this era. This study aimed to assess the relationship between AF and totally occlusive in-stent restenosis (ISR) in femoropopliteal (FP) lesions.

Methods

In this study, 363 patients (461 stents) who underwent endovascular therapy with de novo stent implantation in our hospital between April 2007 and December 2016 were retrospectively evaluated. The patients were divided into two groups according to the AF status (AF group, 61 patients; sinus group, 302 patients). The primary endpoint was the incidence of totally occlusive ISR within 3 years. The secondary endpoint was the incidence of acute limb ischemia (ALI) due to FP stent occlusion.

Results

Baseline characteristics were similar, except for higher age and a lower prevalence of dyslipidemia in the AF group. The incidence of a totally occlusive ISR was higher in the AF group than in the sinus group (29.5% vs. 14.6%, p=0.004). A multiple Cox regression model suggested that presence of AF (hazard ratio, 2.10) and CTO lesion (hazard ratio, 1.97) which were the independent predictors of a totally occlusive ISR within 3 years. The incidence of ALI was significantly higher in the AF group than in the sinus group (3.9% vs. 0%, p=0.0001). In the AF group, the introduction of an anticoagulant did not prevent the occurrence of totally occlusive ISR (p=0.71) for ALI (p=0.79).

Conclusions

AF is independently associated with totally occlusive ISR of FP stents; however, anticoagulant use does not prevent stent occlusion.

Platelet/lymphocyte ratio for prediction of no-reflow phenomenon in ST-elevation myocardial infarction managed with primary percutaneous coronary intervention

Background

Coronary no-reflow phenomenon in ST-segment elevation myocardial infarction (STEMI) is associated with a poor clinical outcome. Although its pathophysiology is not fully understood, a deregulated systemic inflammatory response plays an important role. We aimed to explore the relationship between platelet\lymphocyte ratio (PLR) and no-reflow in patients with acute STEMI who were treated with a primary percutaneous coronary intervention (PPCI).

Methods

A total of 200 patients with STEMI undergoing PPCI were included in the study. Transthoracic echocardiographic examination was performed to assess left ventricular (LV) ejection fraction (EF) and wall motion score index. Blood samples were assayed for platelet and lymphocyte count before PPCI. No-reflow was defined as coronary blood flow thrombolysis in myocardial infarction grade ≤II.

Results

No-reflow was observed in 58 (29%) of STEMI patients following PPCI. PLR was significantly higher in hypertensive patients compared to normotensive patients (144.7±91.6 vs. 109.1±47.1, respectively, P<0.001) and in the no-reflow group compared to the normal reflow group (214±93 vs. 101.6±51.3, respectively, P<0.0001). Logistic regression analysis revealed that PLR (β: 0.485, 95% CI: -0.006-0.001, P<0.002) and LV EF (β: 0.272, 95% CI: 0.009-0.034, P<0.001) were independent predictors of no-reflow after PPCI.

Conclusion

Pre-procedural increase in PLR is predictive of the no-reflow phenomenon following PPCI in STEMI patients.

Relevance for Patients

No reflow phenomenon is an unfavorable complication following PPCI in patients with acute STEMI. High pre-procedural PLR is an independent predictor of reperfusion failure and helps to identify patients who require prophylactic treatment.

Differential cytokine contributions of perivascular haematopoietic stem cell niches

Arterioles and sinusoids of the bone marrow (BM) are accompanied by stromal cells that express nerve/glial antigen 2 (NG2) and leptin receptor (LepR), and constitute specialized niches that regulate quiescence and proliferation of haematopoietic stem cells (HSCs). However, how niche cells differentially regulate HSC functions remains unknown. Here, we show that the effects of cytokines regulating HSC functions are dependent on the producing cell sources. Deletion of chemokine C-X-C motif ligand 12 (Cxcl12) or stem cell factor (Scf) from all perivascular cells marked by nestin-GFP dramatically depleted BM HSCs. Selective Cxcl12 deletion from arteriolar NG2+ cells, but not from sinusoidal LepR+ cells, caused HSC reductions and altered HSC localization in BM. By contrast, deletion of Scf in LepR+ cells, but not NG2+ cells, led to reductions in BM HSC numbers. These results uncover distinct contributions of cytokines derived from perivascular cells in separate vascular niches to HSC maintenance.

Predictors of no- reflow during primary angioplasty for acute myocardial infarction, from Medical College Hospital, Trivandrum

Background

Primary angioplasty (PCI) for acute myocardial infarction is associated with no-reflow phenomenon, in about 5–25% of cases. Here we analysed the factors predicting no reflow .

Methods

This was a case control study of consecutive patients with acute myocardial infarction who underwent Primary PCI from August 2014 to February 2015.

Results

Of 181 patients who underwent primary PCI, 47 (25.9%) showed an angiographic no-reflow phenomenon. The mean age was 59.19 ± 10.25 years and females were 11%.

Univariate predictors of no reflow were age >60 years (OR = 6.146, 95%CI 2.937–12.86, P = 0<0.001), reperfusion time >6 h (OR = 21.94, 95%CI 9.402–51.2, P = < 0.001), low initial TIMI flow (≤1) (OR = 12.12, 95%CI 4.117–35.65, P < 0.001), low initial TMPG flow (≤1) (OR = 36.19, 95%CI 4.847–270.2, P < 0.001) a high thrombus burden (OR = 11.04,95%CI 5.124–23.8, P < 0.001), a long target lesion (OR = 8.54, 95%CI 3.794–19.23, P < 0.001), Killip Class III/IV(OR = 2.937,95%CI 1.112–7.756,P = 0.025) and overlap stenting(OR = 3.733,95%CI 1.186–11.75,P = 0.017).

Multiple stepwise logistic regression analysis predictors were: longer reperfusion time > 6 h (OR = 13.844, 95%CI 3.214–59.636, P = <0.001), age >60 years (OR = 8.886, 95%CI 2.145–36.80, P = 0.003), a long target lesion (OR = 8.637, 95%CI 1.975–37.768, P = 0.004), low initial TIMI flow (≤1) (OR = 20.861, 95%CI 1.739–250.290, P = 0.017).

Conclusions

It is important to minimize trauma to the vessel, avoid repetitive balloon dilatations use direct stenting and use the shortest stent if possible.

Role of endothelin in microvascular dysfunction following percutaneous coronary intervention for non-ST elevation acute coronary syndromes: a single-centre randomised controlled trial

OBJECTIVES

Percutaneous coronary intervention (PCI) for acute coronary syndromes frequently fails to restore myocardial perfusion despite establishing epicardial vessel patency. Endothelin-1 (ET-1) is a potent vasoconstrictor, and its expression is increased in atherosclerosis and after PCI. In this study, we aim to define the role of endothelin in regulating coronary microvascular blood flow and myocardial perfusion following PCI in patients with non-ST elevation acute coronary syndromes (NSTACS), by assessing whether adjunctive therapy with a selective endothelin A (ETA) receptor antagonist acutely improves postprocedural coronary microvascular blood flow.

METHODS

In a randomised, double-blinded, placebo-controlled trial, 23 NSTACS patients were enrolled to receive an intracoronary infusion of placebo (n=11) or BQ-123 (n=12) immediately before PCI. Post-PCI coronary microvascular blood flow and myocardial perfusion were assessed by measuring Doppler-derived average peak velocity (APV), and cardiac biomarker levels were quantified.

RESULTS

Compared with the placebo group, APV was significantly higher in the drug group immediately after PCI (30 (20, 37) vs 19 (9, 26) cm/s; p=0.03). Hyperaemic APV, measured post-adenosine administration, was higher in the BQ-123 group, but the difference did not achieve statistical significance (56 (48, 72) vs 46 (34, 64) cm/s; p=0.090). Maximum coronary flow reserve postprocedure was not different between the two groups (2.1 (1.6, 2.3) vs 2.5 (1.8, 3.0)). Per cent change in creatine kinase isoenzyme MB from the time of PCI to 8 and 16 hours post-PCI was significantly lower in the drug group compared with the placebo group (-17 (-26, -10) vs 26 (-15, 134); p=0.02 and -17 (-38, 14) vs 107 (2, 446); p=0.007, respectively).

CONCLUSIONS

Endothelin is a mediator of microvascular dysfunction during PCI in NSTACS, and adjunctive selective ETA antagonist may augment myocardial perfusion during PCI.

TRIAL REGISTRATION NUMBER

NCT00586820; Results.

Evaluation of Microvascular Disease and Clinical Outcomes

Although coronary microcirculatory dysfunction occurs in numerous cardiac conditions and influences prognosis, it has been largely ignored in clinical practice due to the lack of adequate methods for its assessment. Microcirculatory dysfuntion may result from a variety of causes, including structural remodelling (arterioles or capillaries), dysregulation (paradoxical arteriolar vasoconstriction), hypersensitivity to vasoactive factors or adrenergic drive, and extravascular compression of collapsable elements. Thus, the selection of a method to interrogate coronary microcirculation should be based on the suspected cause of dysfunction. This article reviews such assessment tools and their prognostic information.

Impact of runoff grade after endovascular therapy for femoropopliteal lesions

BACKGROUND

We conceived a new method, runoff grade, to evaluate runoff after endovascular therapy (EVT). We evaluated the validity of using runoff score based on angiographic findings.

METHODS

The subjects were 859 consecutive patients (males, 69%; mean age, 73.0 ± 9.0 years) who underwent EVT for de novo femoropopliteal lesions at Kokura Memorial Hospital. We evaluated the postprocedural tibial runoff, named it runoff grade, classified it into 0 through 2, and retrospectively assessed the relationship with the outcome of EVT. Primary, secondary, and assisted primary patency rates and freedom from major adverse limb events (MALE) were compared between runoff grades.

RESULTS

The mean follow-up period was 31 ± 25 months. The lesion length was 91.5 ± 83.0 mm. The rate of stent use was 52.0%. The primary patency rates at 1, 2, and 3 years were 68.1%, 59.1%, and 53.9%; the secondary patency rates were 90.9%, 88.1%, and 85.9%; the assisted primary patency rates were 79.4%, 72.6%, and 68.5%; and freedom from MALE was 72.5%, 64.8%, and 61.0%, respectively. The primary patency rates at 1, 2, and 3 years were significantly lower in the runoff grade 0 group than in the other groups (55.5% vs 66.7% and 75.6%; 35.8% vs 57.6% and 69.2%; 35.8% vs 53.3% and 60.9% for grade 0, 1, 2, respectively; log-rank, P < .0001). Secondary patency rate (78.5% vs 91.8% and 91.8%; 76.3% vs 88.6% and 89.9%; 72.8% vs 86.3% and 88.2%, respectively; P = .015), assisted primary patency rate (67.0% vs 78.5% and 85.1%; 56.9% vs 71.6% and 79.3%; 47.6% vs 68.0% and 74.8%; respectively, P = .0002), and freedom from MALE (60.8% vs 71.2% and 79.4%; 44.3% vs 64.0% and 72.6%; 36.6% vs 60.7% and 68.5%, respectively; P < .0001) were also similar. After adjustment for age, gender, diabetes, hemodialysis, critical limb ischemia, TransAtlantic Inter-Society Consenus II classification, and stent use, runoff grade was an independent predictor of primary patency.

CONCLUSIONS

Vessels with runoff grade 0 had significantly worse cumulative outcomes. Our results suggested that runoff grade seemed to play an important role to keep the primary patency.

Acceleration time of systolic coronary flow velocity to diagnose coronary stenosis in patients with microvascular dysfunction

BACKGROUND

The aim of this study was to test whether acceleration time of systolic coronary flow velocity could contribute to the diagnosis of coronary stenosis in patients with microvascular dysfunction, on the basis of the hypothesis that systolic coronary flow is less influenced by microvascular function because of compressed myocardium.

METHODS

Coronary flow velocity was assessed in the left anterior descending coronary artery during hyperemia with intravenous adenosine by echocardiography in 502 patients who were scheduled for coronary angiography because of coronary artery disease and significant valvular disease. Coronary flow velocity reserve (CFVR) and the percentage acceleration time (%AT), as the percentage of the time from the beginning to the peak of systolic coronary flow over systolic time during hyperemia, were calculated. The diagnostic ability of CFVR and %AT for angiographic coronary artery stenosis was then analyzed. As invasive substudies, fractional flow reserve and %AT by a dual-sensor (pressure and Doppler velocity) guidewire were measured simultaneously with %AT on transthoracic echocardiography (n = 14).

RESULTS

Patients with coronary stenosis had significantly lower CFVR (1.7 ± 0.4) and greater %AT (65 ± 9%) compared with those without stenosis (2.6 ± 0.6 and 50 ± 13%, respectively). Percentage acceleration time by Doppler echocardiography was in good agreement with %AT (r = 0.98) and fractional flow reserve (r = 0.74) invasively measured by dual-sensor guidewire. Cutoff values of CFVR and %AT were determined as 2.0 and 60% in receiver operating characteristic curve analysis. The sensitivity, specificity, and accuracy of CFVR to detect coronary stenosis were 71.1%, 77.3%, and 75.4%, while those of %AT were 83.4%, 71.8%, and 75.4%, respectively. In addition, %AT provided high accuracy to detect coronary stenosis, especially in patients with previous myocardial infarctions, valvular disease, and left ventricular hypertrophy (81.1%, 84.1%, and 73.4%, respectively).

CONCLUSIONS

The %AT of systolic coronary flow velocity is a promising marker to diagnose coronary stenosis in patients with microvascular dysfunction.

Prevalence, correlation and clinical outcome of intra-procedural stent thrombosis in patients undergoing primary percutaneous coronary intervention for acute coronary syndrome

OBJECTIVES

To assess the occurrence, correlation, and clinical outcome of intraprocedural stent thrombosis (IPST) in patients undergoing primary percutaneous coronary intervention (PCI) in the setting of acute coronary syndromes (ACSs).

BACKGROUND

Stent thrombosis (ST), a rare complication of PCI, is more common in the setting of ACS. It is not known whether IPST carries the same prognosis as postprocedural ST.

METHODS

This retrospective study comprised a review of 1,901 consecutive ACS patients who received primary PCI in our center from January 2006 to January 2011. IPST was defined as new, reappearing or increased thrombus within the deployed stent before the index PCI procedure was completed. All angiograms were independently reviewed frame by frame for the incidence of IPST. Patients with and without IPST were compared with respect to clinical characteristics, angiographic parameters, and major adverse cardiac events (MACEs) at 30 days and 1-year follow-up.

RESULTS

Overall, there were 23 cases of IPST detected, thus, the prevalence of IPST was 1.2%. There were no significant differences in baseline clinical characteristics between the 2 groups. Patients with compared to those without IPST had significantly more bifurcation lesions involved, and more thrombus burden at baseline. IPST group compared to no IPST group had more MACEs on 30 days (26.1% vs. 8.7%, P = 0.01) and 1-year follow-up (30.4% vs. 14.4%, P = 0.02).

CONCLUSIONS

IPST was a rare complication of PCI in the setting of ACS. It correlated with lesion morphology, presence of thrombus at baseline and was more likely to cause MACEs in 30 days and 1-year follow-up.

Incidence and outcomes of no-reflow phenomenon during percutaneous coronary intervention among patients with acute myocardial infarction

Previous studies describing the no-reflow phenomenon in patients with acute myocardial infarction (AMI) undergoing percutaneous coronary intervention (PCI) were largely confined to single-center studies or small registries. To better characterize the incidence, predictors, and outcomes of the no-reflow phenomenon in a large contemporary population, we analyzed patients with AMI who were undergoing PCI of native coronary artery stenoses in the CathPCI Registry from January 1, 2004 through September 5, 2008 (n = 291,380). The angiographic no-reflow phenomenon was site reported using a standardized definition. No-reflow developed in 2.3% of the patients with AMI (n = 6,553) during PCI. Older age, ST-segment elevation AMI, prolonged interval from symptom onset to admission, and cardiogenic shock were clinical variables independently associated with the development of no-reflow (p <0.001). The angiographic factors independently associated with no-reflow included longer lesion length, higher risk class C lesions, bifurcation lesions, and impaired preprocedure Thrombolysis In Myocardial Infarction flow (p <0.001). No-reflow was associated with greater in-hospital mortality (12.6% vs 3.8%, adjusted odds ratio 2.20, 95% confidence interval 1.97 to 2.47, p <0.001) and unsuccessful lesion outcome (29.7% vs 6.6%, adjusted odds ratio 4.70, 95% confidence interval 4.28 to 5.17, p <0.001) compared to patients without no-reflow. In conclusion, the development of no-reflow, although relatively uncommon during PCI for AMI, is associated with adverse clinical outcomes. Upfront strategies to reduce the incidence of no-reflow could be considered for high-risk patients to improve outcomes.

Assessment of coronary artery flow velocity pattern as a long-term predictor of left ventricular function and cardiac events after percutaneous coronary intervention in anterior acute myocardial infarction

BACKGROUND

Coronary flow velocity (CFV) can be used to assess short-term left ventricular function recovery and the clinical prognosis of patients with acute myocardial infarction (AMI). We evaluated CFV as a predictor of long-term left ventricular function recovery and cardiac events in patients with anterior wall AMI.

METHODS AND RESULTS

CFV pattern of the distal left anterior descending (LAD), wall motion score index (WMSI) and left ventricular ejection fraction (LVEF) were recorded at the points of time within 24 hours, 3 days, 6 months, and 3 years after percutaneous coronary intervention (PCI) in 50 consecutive patients with anterior wall AMI. The clinical data were collected. Patients were divided into two groups based on diastolic deceleration time (DDT) 3 days after PCI. Compared with 3 days, LVEF and WMSI in group A (DDT>600 ms, n=20) improved in 6 months and 3 years (p<0.01), but they were unchanged in group B (DDT< or =600 ms, n=30). The incidence of cardiac events was higher in group B than in group A during 6 months (p<0.01).With a 3-year follow up, the incidence of chronic heart failure was higher in group B than in group A (p=0.009).

CONCLUSION

CFV could be used as a predictor of long-term left ventricular function recovery and cardiac events in patients with anterior wall AMI.

The effect of thrombolytic therapy on left ventricular aneurysm formation in acute myocardial infarction: relationship to successful reperfusion and vessel patency

BACKGROUND

Although there is increasing evidence for the beneficial effect of thrombolytic therapy on global left ventricular (LV) function in acute myocardial infarction (AMI), the data concerning the early effect of thrombolytic therapy on the incidence of left ventricular aneurysm (LVA) formation and its relationship to clinical and angiographic determinants are limited.

HYPOTHESIS

The study aimed to determine the independent factors involved in the development of LVA and to evaluate whether thrombolytic therapy has any preventive effect on the development of LVA in AMI.

METHODS

In all, 350 consecutive patients suffering from a first attack of AMI were included. Of these, 205 who arrived within 12 h of onset of symptoms received thrombolytic therapy (thrombolytic group) and the remaining 145 patients served as control group. All patients received aspirin and maximal-dose anticoagulation with intravenous heparin therapy. Early successful reperfusion was assessed by enzymatic and electrocardiographic evidence, and late vessel patency was evaluated according to Thrombolysis in Myocardial Infarction (TIMI) classification. Patients with TIMI grade 2 or 3 flow were considered to have vessel patency.

RESULTS

The overall incidence of LVA was 11.7% (41/350), and no statistical difference was found between the incidence of LVA between the two groups (11.7 vs. 11.7%, p>0.05). However, the patients receiving thrombolytic therapy and exhibiting a patent infarct-related artery (PIRA) (n = 125, 61%), had a significantly reduced incidence of LVA compared with those who did not (7.2 vs. 18.8%, p= 0.015). In univariate analysis, vessel patency, proximal left anterior descending artery (LAD) stenosis, total LAD occlusion, multivessel disease, and hypertension were found to be important factors in LVA formation after AMI. After adjustment for other clinical and angiographic variables, total LAD occlusion (odds ratio [OR] 3.62,95% confidence interval [CI] 2.45-8.42, p = 0.0014), absence of PIRA (OR 2.92, 95% CI 1.41-09, p = 0.0037) and proximal LAD stenosis (OR 2.11, 95% CI 1.05-4.71, p = 0.045) remained the independent determinants of LVA formation after AMI.

CONCLUSION

Our data indicate that not all patients who received thrombolytic therapy, but only those with PIRA had evidently reduced the incidence of LVA. Patients with total LAD occlusion, with proximal LAD stenosis, and without PIRA were found to have increased risk for formation of LVA after AMI. These findings indicate that the presence of vessel patency has a preventive effect on LVA formation in AMI.

Concordant improvements in coronary flow reserve and ST-segment resolution during percutaneous coronary intervention for acute myocardial infarction: a benefit of postconditioning

OBJECTIVE

To assess the effect of ischemic postconditioning on indices of coronary microvascular function during percutaneous coronary intervention (PCI) for acute ST segment elevation myocardial infarction (STEMI).

BACKGROUND

Myocardial tissue level perfusion remains suboptimal in many patients with STEMI despite restoration of antegrade flow in the epicardial coronary artery.

METHODS

Twenty-four patients with an evolving anterior STEMI were randomized to undergo a previously-validated ischemic postconditioning protocol or usual care during PCI. The extent of resolution of ST segment elevation along with Doppler-tip catheter velocimetry was used as indices of myocardial reperfusion and microvascular function, respectively.

RESULTS

Postconditioned patients exhibited a greater, and therefore more rapid, extent of ST segment resolution (postconditioning, 70% +/- 15%; control, 48% +/- 16%; P = 0.0002) by the end of the procedure. Postconditioned patients also exhibited a greater hyperemic coronary vasodilator response at the completion of the procedure (coronary flow velocity reserve, CFVR: postconditioning, 2.2 +/- 0.1; control, 1.5 +/- 0.1; P < 0.0001). The end-procedure CFVR was directly related to the extent of the ST segment resolution (r = 0.85) but inversely related to the absolute magnitude of ST segment elevation at end procedure (r = -0.76). Peak serum creatine kinase was significantly lower in postconditioned patients (postconditioning, 1,524 +/- 435 IU/l; control, 1,862 +/- 561 IU/l; P = 0.03).

CONCLUSIONS

Ischemic postconditioning, as described, can be expeditiously performed during PCI for STEMI. Concordant changes in coronary flow reserve and ST segment resolution, measures of microcirculatory function, and myocardial perfusion, were greater in postconditioned patients.

Comparison of accuracy in the prediction of left ventricular wall motion changes between invasively assessed microvascular integrity indexes and fluorine-18 fluorodeoxyglucose positron emission tomography in patients with ST-elevation myocardial infarction

We compared the accuracy in predicting regional wall motion score index (RWMSI) changes between microvascular integrity indexes measured during primary percutaneous coronary intervention (PCI) and fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) in ST-elevation myocardial infarction (STEMI). Fifty patients with STEMI were enrolled. Microvascular integrity indexes were measured using an intracoronary Doppler wire and a pressure wire after primary PCI. We performed FDG-PET 7 days after PCI. RWMSI on follow-up echocardiogram (5.8 +/- 1.7 months) revealed good correlations with coronary flow reserve (r = -0.442, p = 0.002), diastolic deceleration time (r = -0.511, p <0.001), microvascular resistance index (r = 0.443, p = 0.002), coronary wedge pressure (r = 0.474, p <0.001), and FDG uptake rate (r = -0.571, p <0.001). There were no significant differences in areas under the curve for predicting RWMSI changes between microvascular integrity indexes and FDG-PET (coronary flow reserve 0.696, diastolic deceleration time 0.731, microvascular resistance index 0.748, coronary wedge pressure 0.694, Thrombolysis In Myocardial Infarction myocardial perfusion grade 0.702, and FDG-PET 0.755). In conclusion, microvascular integrity indexes assessed during primary PCI are useful and comparable to FDG-PET in predicting left ventricular functional changes in STEMI.

Distal protection device protects microvascular integrity during primary percutaneous intervention in acute myocardial infarction: A prospective, randomized, multicenter trial

BACKGROUND

Distal protection during primary angioplasty in acute myocardial infarction (AMI) is the subject of recent controversy. The present study was designed to determine whether the distal embolic protection preserves myocardial microvascular integrity and improves clinical outcomes in patients with AMI.

METHODS

A total of 116 AMI patients presenting within 12 h of onset of symptoms were enrolled at 7 angioplasty centers. They were randomly assigned to either primary angioplasty with distal protection group (DP; n=60) or angioplasty alone group (Controls; n=56).

RESULTS

After primary angioplasty, achievement of final Thrombolysis In Myocardial Infarction (TIMI) grade 3 and TIMI Myocardial Perfusion (TMP) grade 3 were more frequent in the DP group than in the control group [58/60 (96%) vs. 43/56 (81%), p=0.016; and 39/60 (65%) vs. 20/56 (38%), p=0.001, respectively]. After primary angioplasty, the baseline and hyperemic averaged peak velocities were significantly higher (23.2+/-11.5 vs. 18.0+/-6.9 cm/s, p=0.029; and 39.2+/-16.7 vs. 30.6+/-10.8 cm/s, p=0.014, respectively) and the baseline and hyperemic microvascular resistance indices were significantly lower (4.18+/-2.22 vs. 5.34+/-2.25 mm Hg cm(-1) s, p=0.036; and 2.38+/-1.39 vs. 3.11+/-1.32 mm Hg cm(-1) s, p=0.030, respectively) in the DP group. Patients in the DP group showed more favorable phasic coronary flow pattern in diastolic deceleration time (679+/-262 vs. 519+/-289 ms, p=0.035; and 751+/-246 vs. 616+/-269 ms, p=0.035, respectively). Major adverse cardiac events at 6 months occurred with similar frequency in both groups (8.7% vs. 11.1%, p=0.400).

CONCLUSIONS

Distal protection device effectively preserves microvascular integrity during primary angioplasty in AMI. Distal protection, however, did not improve clinical outcomes.

Relationship between microvascular resistance and perfusion in patients with reperfused acute myocardial infarction

Despite its prognostic importance, accurate assessment of microvascular perfusion in patients with ST elevation acute myocardial infarction (STEMI) is difficult. As a new tool, the index of microvascular resistance (IMR) measurement provides us a new opportunity for interrogating microvascular condition after STEMI. In this study, we measured IMR in infarct-related artery (IRA) and explored its relation with other indices which have been suggested to evaluate microvascular perfusion in patients with reperfused STEMI.

METHODS

Forty-two patients with STEMI treated successfully with primary percutaneous coronary intervention (pPCI) were prospectively included. After 48 hours following pPCI, patients were recatheterized and IMR, coronary flow reserve (CFR), systolic and mean coronary wedge pressures (CWPs and CWPm) pressure-derived collateral flow index (CFIp) were measured in IRA by using intracoronary pressure-temperature sensor tipped guide wire. Myocardial blush grade was assessed from the second angiogram. Coronary flow velocity pattern (diastolic deceleration time: DDT) was examined with transthoracic echocardiography 48 hours after pPCI. Percentage of ST-segment recovery was calculated from surface ECG (STR%).

RESULTS

IMR well correlated with CWPs (r = 0.70, P < 0.001), CWPm (r = 0.59, P < 0.001), CFIp (r = 0.65, P < 0.001), CFR (r =-0.50, P = 0.001), and DDT (r =-0.59, P = 0.001). Correlations of IMR to non/semiinvasive indices like myocardial blush grades (MBG) (r =-0.42, P = 0.007) and STR (r =-0.37, P = 0.024) are somewhat weaker.

CONCLUSION

Given its simplicity of measurement, independence from the presence of an epicardial stenosis, and good correlation with all measures of microvascular obstruction used in this study, IMR may prove to be a valuable modality for evaluating the microcirculation.

Intracoronary boluses of adenosine and sodium nitroprusside in combination reverses slow/no-reflow during angioplasty: a clinical scenario of ischemic preconditioning

No or slow reflow following percutaneous coronary intervention (PCI), despite the presence of a patent epicardial vessel, is a serious complication resulting in increased morbidity and mortality. In the present study, we have evaluated the combination therapy of adenosine and sodium nitroprusside administered as sequential intracoronary (IC) boluses on no-reflow during PCI. Seventy-five high risk acute coronary syndrome patients who underwent PCI with evidence of initial less than TIMI (thrombolysis in myocardial infarction) III flow or developed deterioration in TIMI flow during the procedure were randomized to prophylactic administration of multiple boluses of IC saline solution, adenosine (12 microg/bolus) or the combination of adenosine (12 microg/bolus) and sodium nitroprusside (50 microg/bolus), sequentially. Assessment of TIMI and the TMP (tissue myocardial perfusion) grade was done and major adverse cardiac events (MACE) were assessed at the end of 6 months. Slow or no-reflow was persistent in 70% patients receiving saline solution, 31% patients receiving adenosine, and 4% patient receiving the combination. IC injection with saline solution did not produce improvement in TIMI flow or TMP grade. IC injection with combination resulted in greater improvement of TIMI flow and TMP grade. The crossover of patients with no-reflow in saline solution group or adenosine with combination treatment was associated with reestablishment of TIMI II in 4 and TIMI III in 20 patients. Our data suggest that combination therapy of adenosine and nitroprusside is safe and provides better improvement in coronary flow and MACE as compared with IC adenosine alone in cases of impaired flow during coronary interventions.

Transesophageal Doppler echocardiographic detection of intramyocardial collateral flow to the right coronary artery and changes in the flow to the inferior left ventricular wall immediately after coronary artery bypass grafting

This study examined the feasibility of Doppler transesophageal echocardiography (TEE) to detect collateral flow to the myocardium supplied by the right coronary artery (RCA) in the inferior left ventricular wall. Forty-four patients who underwent elective coronary artery bypass grafting (CABG) were prospectively studied. Presence of collateral flow to the RCA was diagnosed on preoperative angiography using the Rentrop score and by intraoperative Doppler TEE. Agreement of the 2 methods was analyzed by calculating the kappa coefficient. Collateral flow was present on preoperative angiography in 19 patients and absent in 25 patients. Intraoperative TEE detected collateral flow in the inferior wall in 15 patients (79%) with and 3 patients (12%) without angiographic collaterals, resulting in a kappa coefficient for agreement of 0.67 (95% confidence interval 0.45 to 0.90). Baseline collateral flow disappeared after CABG in 12 of 14 patients with grafting of the RCA but persisted in all patients without such grafting. Physiologic flow in the inferior wall was detected by TEE in a total of 27 patients at baseline and in 38 patients after CABG (p = 0.0018); its peak velocity increased after surgery only in the subgroup of patients with grafting of the RCA. In conclusion, these findings indicate that Doppler TEE may detect collateral flow in the inferior left ventricular wall, and that there are typical changes in collateral and physiologic flow after CABG.

No-reflow phenomenon and prognosis in patients with acute myocardial infarction

The rapid restoration of coronary flow to the jeopardized myocardium has become an essential part of therapy after acute myocardial infarction. Despite an open infarct-related artery, breakdown of or obstruction to coronary microvasculature can markedly reduce blood flow to the infarct zone. This effect is known as the no-reflow phenomenon. Advances in imaging modalities have improved visualization of no reflow, showing its frequency to be higher than was estimated by clinical judgment alone. This phenomenon is important because it correlates with infarct size and provides useful prognostic information. No reflow is associated with reduced left ventricular ejection fraction, left ventricular remodeling, and poor clinical outcomes, placing patients with this effect in a high-risk group among reperfused patients. The focus of reperfusion therapy is shifting towards improved myocardial perfusion, which could promote functional recovery of viable muscle, reduce infarct expansion, and increase the delivery of blood-borne components, thereby accelerating the healing process. Various pharmacologic interventions and catheter-based devices to retrieve embolic materials have been proposed. Further studies to improve understanding of the pathophysiology of microvascular dysfunction will, however, help in the further development of preventive and therapeutic strategies. In this article, I discuss in depth the data available on the no-reflow phenomenon.

Increased Tei index suggests absence of adequate coronary reperfusion in patients with first anteroseptal acute myocardial infarction

BACKGROUND

The estimation of coronary reperfusion in acute myocardial infarction (AMI) is important. The left ventricular (LV) Tei index is a noninvasive and sensitive parameter expressing overall LV function. We hypothesized that patients without good coronary reperfusion have worse LV function with a higher or worse Tei index compared to those with good reperfusion.

METHODS AND RESULTS

In 85 patients with first anteroseptal AMI, without other cardiac lesions such as prior myocardial infarction, LV hypertrophy or valvular disease, the Tei index was measured using Doppler echocardiography immediately after patients' arrival to the hospital, and the Thrombolysis in Myocardial Infarction (TIMI) grade was evaluated through subsequent coronary angiography. The Tei index was significantly greater in patients who did not have TIMI score of 3 compared to those with a TIMI of 3 (0.60+/-0.13 vs 0.46+/-0.06, p<0.0001). A Tei index >0.50 as the criteria for the absence of TIMI 3 had the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 75, 86, 94, 54 and 78%, respectively.

CONCLUSION

An increased Tei index suggests the absence of adequate coronary reperfusion in patients with first anterior AMI without other lesion.

Coronary Flow Velocity Pattern Assessed Noninvasively by Transthoracic Color Doppler Echocardiography Serves as a Predictor of Adverse Cardiac Events and Left Ventricular Remodeling in Patients with Acute Myocardial Infarction

BACKGROUND

Quantitative assessment of microvascular injury is possible in patients with reperfused anterior myocardial infarction by invasive method. Coronary flow velocity patterns can also be assessed by transthoracic color Doppler echocardiography (TTCDE).

OBJECTIVES

The purpose of this study was to determine whether the coronary flow velocity pattern assessed by TTCDE serves as a predictor of adverse cardiac events and left ventricular remodeling.

METHODS

The study population consisted of 64 consecutive patients. We could analyze coronary flow velocity patterns by TTCDE in 59 of 64 patients (92%) after coronary intervention. The patients were followed up for the occurrence of complications and underwent serial measurement of left ventricular volumes.

RESULTS

In patients with a short deceleration time of diastolic flow velocity, the frequency of adverse cardiac events and left ventricular remodeling was higher.

CONCLUSION

It is possible to predict clinical outcome by assessing coronary flow velocity pattern by TTCDE.

Effect of Distal Protection Device on the Microvascular Integrity in Acute Myocardial Infarction During Primary Percutaneous Coronary Intervention

BACKGROUND

The use of a distal protection device during primary percutaneous coronary intervention (PCI) in acute myocardial infarction (AMI) may preserve the microvascular integrity of the myocardium.

METHODS AND RESULTS

A total of 58 consecutive patients with AMI, who had undergone primary PCI within 24 h after onset, were enrolled (30 patients with the PercuSurge GuardWire System, 28 without). The coronary flow velocity reserve was not different between the 2 groups. In patients with a distal protection device, the post-PCI Thrombolysis In Myocardial Infarction myocardial perfusion grades (TMP) were more favorable (TMP 0/1: 13.3%, TMP 2: 23.3%, TMP 3: 63.4% vs TMP 0/1: 35.7%, TMP 2: 35.7%, TMP 3: 28.6%, p=0.023). These patients also exhibited lower basal and hyperemic microvascular resistance index levels (4.33+/-2.22 vs 5.55+/-2.36 mmHg . cm(-1) . s, p=0.047; 2.39+/-1.40 vs 3.14+/-1.36 mmHg . cm(-1) . s, p=0.045, respectively), and longer basal diastolic deceleration time (679+/-273 vs 519+/-289 ms, p=0.035) after PCI.

CONCLUSION

Distal protection with the PercuSurge GuardWire system may effectively preserve the microvascular integrity of the myocardium during primary PCI in AMI patients.

Usefulness of a new grading system based on coronary flow velocity pattern in predicting outcome in patients with acute myocardial infarction having percutaneous coronary intervention

In acute myocardial infarction, the coronary blood flow velocity waveform changes with the damage in the infarcted myocardium. We developed a grading system using the shorter diastolic deceleration time (DDT), appearance of systolic flow reversal (SFR), and disappearance of systolic anterograde flow. We studied 72 patients with a first anterior acute myocardial infarction. Doppler guidewire monitoring and myocardial contrast echocardiography were performed 10 and 15 minutes after percutaneous coronary intervention, and left ventriculography was performed at discharge (24 +/- 2 days) to measure regional wall motion (SD/chord). Patients were classified into 4 groups according to the coronary blood flow velocity pattern: group I (n = 39), DDT >or=600 ms; group II (n = 10), DDT <600 ms; group III (n = 17), DDT <600 ms with SFR; and group IV (n = 14), DDT <600 ms with SFR and without systolic anterograde flow. The no-reflow phenomenon was observed in no patients in group I, in 3 in group II, in 11 in group III, and all 14 patients in group IV. Regional wall motion was highest in group I and decreased with increasing group number (groups I, II, III, and IV, -1.45 +/- 0.80, -2.36 +/- 0.60, -2.90 +/- 0.50, and -3.20 +/- 0.52 SD/chord, respectively). With the progression of damage in the infarcted myocardium, the DDT shortened first, followed by the appearance of SFR, and then the disappearance of systolic anterograde flow. In conclusion, analysis of the coronary blood flow velocity pattern allows assessment of the severity of microvascular dysfunction and prediction of left ventricular functional outcomes.

Distal embolization during primary angioplasty: histopathologic features and predictability

BACKGROUND

Distal embolization during primary percutaneous coronary interventions (PCIs) may affect myocardial reperfusion. We evaluated the prevalence and features of embolization during primary PCI and its relationship with clinical and angiographic variables.

METHODS

Forty-six consecutive patients with acute myocardial infarction underwent primary PCI with a filter-based distal protection device. Histopathologic analysis was performed on retrieved embolic fragments, assessing the presence and relative amount of fibrin, necrosis, lipid droplets, collagen, mucopolysaccharides, and leukocytes, as well as the total debris volume. Such variables were related to baseline clinical and angiographic variables.

RESULTS

Embolic material was recovered in 41 (89%) of 46 cases, with a mean total debris volume of 1.2 +/- 2.2 mm3. Prevalent histopathologic patterns were organized thrombus (47%), fresh thrombus (29%), and plaque fragments (24%). At multivariate analysis, none of the baseline clinical variables considered significantly predicted the total debris volume. Among angiographic variables, angiographic signs of high thrombus burden (cut-off coronary occlusion pattern or large intracoronary minus image) independently predicted the total debris volume at multivariate analysis (odds ratio 15.8, P < .005). Compared with its nonuse, abciximab did not affect the total number and the mean total volume of embolized material (15 +/- 16 vs 10 +/- 8 fragments, 1.5 +/- 2.5 vs 1.0 +/- 1.9 mm3, respectively, for both P > .20), or its qualitative composition.

CONCLUSIONS

Distal embolization occurs in most patients during primary PCI and mainly consists of plaque fragments and partially organized thrombi, which are likely to be scarcely responsive to antiplatelet drugs. Baseline angiographic signs of a high thrombus burden are the only significant predictors of the extent of distal embolization.

Effect of nicorandil, a K+ATP -channel opener, on coronary capillary architecture and volume after early myocardial ischemia-reperfusion--a 3-dimensional confocal laser microscopic study--

BACKGROUND

Previous experimental and clinical studies have reported that nicorandil, an adenosine triphosphate (ATP)-sensitive K+ channel opener, exerts a beneficial effect on microvascular function and clinical outcome after myocardial ischemia. The present study assessed whether intravenous administration of nicorandil affects the 3-dimensional (3-D) architectural characteristics of capillaries and their volume after early myocardial reperfusion.

METHODS AND RESULTS

Using the hearts of open-chest anesthetized rats, the left anterior descending artery was occluded for 7 min followed by reperfusion. Nicorandil or saline was infused intravenously during occlusion and reperfusion. The entire coronary microvasculature was filled with contrast medium after the hearts were arrested. Capillaries were observed 3-dimensionally by confocal laser scanning microscopy in both the control area and reperfused area of all samples. The capillary volume fraction was computed from the 3-D images. The reperfused area in both the nicorandil and saline groups showed characteristic architectural changes of the capillaries. Capillary volume fraction in the reperfused area was significantly reduced in saline group, compared with nicorandil group [12.7+/-7.2% vs 18.1 +/-5.3% (p<0.01)].

CONCLUSIONS

Intravenous nicorandil administration has a beneficial effect on capillary damage after reperfusion.

Correlation Between Distal Left Anterior Descending Artery Flow Velocity by Transthoracic Doppler Echocardiography and Corrected TIMI Frame Count Before Mechanical Reperfusion in Patients With Anterior Acute Myocardial Infarction

BACKGROUND

This study was designed to determine the utility of transthoracic Doppler echocardiography (TTDE) in evaluating angiographic Thrombolysis in Myocardial Infarction (TIMI) frame count as a quantitative index of coronary reperfusion in patients with anterior acute myocardial infarction (AMI) before mechanical reperfusion.

METHODS AND RESULTS

Color and pulsed TTDE was performed to evaluate distal left anterior descending coronary artery (LAD) reperfusion in 56 consecutive patients with a first anterior AMI before coronary intervention, and these findings were compared with the corrected TIMI frame count (cTFC) by subsequent angiography. Twenty-four of the 56 patients had LAD reperfusion (TIMI 2 or 3) by angiography. Visual antegrade distal LAD flow by color TTDE was detected in 21 of these 24 patients. In the 21 patients, diastolic peak velocity of the distal LAD flow by pulsed TTDE showed a significant correlation with cTFC by angiography (r = -0.74, p < 0.001). The diagnosis of high risk with angiographic cTFC >40 by distal LAD peak velocity <21 cm/s using TTDE had a sensitivity, specificity, and accuracy of 82%, 93%, and 91%, respectively.

CONCLUSION

TTDE enables noninvasive and quantitative evaluation of distal LAD reperfusion in patients with anterior AMI in the acute phase before mechanical reperfusion.

Current assessments of the adequacy of myocardial perfusion during acute MI

For two decades now, the optimal management of acute coronary syndrome has been the early restoration of complete and sustained flow to the jeopardized infarct area. Advances in thrombolytic therapy and percutaneous coronary interventions have contributed significantly to the re-establishment of epicardial flow. However, a body of evidence now strongly indicates that restoration of epicardial flow alone is not sufficient to optimize clinical outcomes. Rather, it has become evident that reperfusion therapy must also involve restoration of microcirculatory reperfusion. Thus, techniques to assess myocardial perfusion during acute myocardial infarction are becoming increasingly relevant for the assessment of patient prognosis.

Impact of flow level on coronary flow velocity pattern. A doppler flow study in patients with first acute myocardial infarction

Analysis of coronary flow velocity pattern has been used to assess microvascular function post acute myocardial infarction (AMI). This study sought to analyze whether the flow level has an impact on parameters of coronary flow velocity pattern. Parameters of coronary flow velocity pattern were determined at baseline and during increased flow due to maximal hyperemia induced by adenosine in 25 patients after PTCA for first AMI using Doppler flow wires. Patients were divided into those with depressed (global wall motion index (GWMI) > or = 1.5; n = 14) and those with preserved (GWMI < 1.5; n = 11) left ventricular (LV) function at 4 weeks. Coronary flow velocity pattern at rest was different between patients with depressed and patients with preserved LV function at follow-up. A difference in flow pattern between the groups remained at increased flow level. However, increase of flow altered parameters of flow pattern. Diastolic deceleration rate (DSR) increased for patients with preserved LV function (53.7+/-25.6 at baseline vs. 67.0+/-29.8 cm/s2 with adenosine) and depressed LV function (95.3+/-58.6 vs. 110.7+/-61.4 cm/s2, respectively, p = 0.0012). Induction of hyperemia resulted also in increased systolic and diastolic peak flow velocity and diastolic deceleration time (DDT). Higher flow had no impact on early systolic retrograde flow, systolic flow duration and diastolic-systolic velocity ratio (DSVR). The coronary flow velocity pattern allows prediction of LV function at 4 weeks after AMI. However, it should be considered that some parameters of the flow velocity pattern are affected by the coronary flow level.

Three-Dimensional Microstructural Abnormality of the Coronary Capillary Network After Myocardial Reperfusion-Comparison Between 'Reflow' and 'No-Reflow'-

BACKGROUND

The 3-dimensional (D) structural abnormalities of the coronary capillary network and capillary volume changes after myocardial reperfusion were investigated using confocal laser scanning microscopy.

METHODS AND RESULTS

Using open-chest anesthetized rats' hearts, the left anterior descending artery (LAD) was occluded for 7 min followed by reperfusion. The hearts were divided into 2 groups: (1) reperfused area stained well by intravenous indocyanine green after reperfusion (Reflow), and (2) lack of staining in the reperfused area (No-reflow). The entire coronary microvasculature was filled with contrast medium using a Langendorff's perfusion system. Capillaries were observed 3-dimensionally in the control and reperfused areas in both the Reflow and No-reflow group and the capillary volume fraction was computed from the 3-D images. The reperfused area in both groups showed decreased capillary diameter with waving and shrinkage configuration. In the No-reflow group, marked interruption of capillary network was observed. In the Reflow group the capillary volume fraction was significantly reduced in the reperfused area compared with the control area (14.8+/-4.1% vs 22.2+/-5.6%, p<0.05). Capillary volume fraction was further decreased in the No-reflow group compared with Reflow (5.3+/-1.4% vs 14.8+/-4.1%, p<0.01).

CONCLUSION

The morphological changes in coronary capillaries after reperfusion were characterized by waving and shrinkage, which resulted in a reduction in capillary volume.

Current concepts in coronary physiology for the interventionalist

Coronary angiography remains the 'gold standard' for the diagnosis of epicardial coronary disease. However, precise quantification of stenosis severity is limited because of the complex three-dimensional geometry of epicardial plaques. To assist the angiographer in lesion assessment, several physiologic measurements have been developed to evaluate stenosis severity, including coronary flow reserve, relative coronary flow reserve and fractional flow reserve. Physiologic lesion assessment can also be an invaluable tool in coronary intervention, evaluating efficacy of angioplasty and stent deployment.

Relation of coronary flow pattern to myocardial blush grade in patients with first acute myocardial infarction

BACKGROUND

Analysis of myocardial blush grade (MBG) and coronary flow velocity pattern has been used to obtain direct or indirect information about microvascular damage and reperfusion injury after percutaneous transluminal coronary angiography for acute myocardial infarction.

OBJECTIVE

To evaluate the relation between coronary blood flow velocity pattern and MBG immediately after angioplasty plus stenting for acute myocardial infarction.

DESIGN

The coronary blood flow velocity pattern in the infarct related artery was determined immediately after angioplasty in 35 patients with their first acute myocardial infarct using a Doppler guide wire. Measurements were related to MBG as a direct index of microvascular function in the infarct zone.

RESULTS

Coronary flow velocity patterns were different between patients with absent myocardial blush (n = 14), reduced blush (n = 7), or normal blush (n = 14). The following variables (mean (SD)) differed significantly between the three groups: systolic peak flow velocity (cm/s): absent blush 10.9 (4.2), reduced blush 14.2 (6.4), normal blush 19.2 (11.2); p = 0.036; diastolic deceleration rate (ms): absent blush 103 (58), reduced blush 80 (65), normal blush 50 (19); p = 0.025; and diastolic-systolic velocity ratio: absent blush 4.06 (2.18), reduced blush 2.02 (0.55), normal blush 1.88 (1.03); p = 0.002. In a multivariate analysis MBG was the only variable with a significant impact on the diastolic deceleration rate (p = 0.034,) while age, infarct location, time to revascularisation, infarct vessel diameter, and maximum creatine kinase had no significant impact.

CONCLUSIONS

The coronary flow velocity pattern in the infarct related epicardial artery is primarily determined by the microvascular function of the dependent myocardium, as reflected by MBG.

Myocardial Reperfusion: Its Assessment and Its Relation to Clinical Outcomes

It has become increasingly apparent that epicardial blood flow restoration is necessary, but not sufficient, to achieve optimal clinical outcomes in the setting of acute coronary syndromes. Indeed, clinical outcomes are strongly associated with myocardial perfusion. The diagnostic tools available to assess myocardial perfusion following acute myocardial infarction and their association with clinical outcomes are reviewed here. Many simple angiographic markers--the Thrombolysis in Myocardial Infarction (TIMI) count frame, TIMI myocardial perfusion grade, pulsatile flow--are all readily available measures and are strongly related to clinical outcomes. Other tools, while accurate, remain limited by their high cost, low availability, and complexity for routine use.

Significance of thrombolysis in myocardial infarction (TIMI) grade 2 flow early after thrombolysis followed by immediate percutaneous coronary intervention in patients with acute myocardial infarction

Although pre-interventional thrombolysis has recently been shown to restore early patency and preserve left ventricular function in patients with acute myocardial infarction, the significance of Thrombolysis in Myocardial Infarction (TIMI) grade flow early after thrombolysis remains unclear. Patients were classified into 3 groups according to TIMI grade flow 45 min after thrombolysis; 38 patients with TIMI grade 0 or 1 flow (group T0) and 46 with TIMI grade 2 flow (group T2) additionally received immediate percutaneous coronary intervention (PCI) and 50 patients with TIMI grade 3 flow (group T3) were treated conservatively after thrombolysis. Although the door-to-balloon times did not differ in groups T0 and T2, group T2 had lower peak creatine kinase, a higher rate of complete (>/=70%) ST resolution and better regional wall motion at discharge as compared with group T0, similar to group T3 (group T2, group T3 vs group T0; 2,857+/-1,756, 2,314+/-1,948 vs 3,779 +/-2,214 mU/ml; 57, 72 vs 34%; -1.5+/-1.6, -1.2+/-1.6 vs -2.2+/-1.6; all p<0.01, respectively). These results suggest TIMI grade 2 flow at 45 min after thrombolysis followed by immediate PCI, as well as TIMI grade 3 flow, is associated with greater myocardial salvage than TIMI grade 0 or 1 flow.

Myocardial viability, coronary flow reserve, and in-hospital predictors of late recovery of contractility following successful primary stenting for acute myocardial infarction

OBJECTIVE

To assess the relation between myocardial viability, coronary flow reserve, and recovery of myocardial contractility after stenting for acute myocardial infarction.

DESIGN

Consecutive sample prospective study.

SETTING

University hospital.

PATIENTS

41 patients with single vessel disease and successful primary stenting for a first acute myocardial infarction.

INTERVENTIONS

(201)Tl single photon emission computed tomography, contrast ventriculography, and intracoronary Doppler performed 7 (1) days after primary stenting.

MAIN OUTCOME MEASURES

Regional contractility recovery assessed by contrast ventriculography at 6 (1) months' follow up.

RESULTS

On univariate analysis, contractility recovery was correlated to prereperfusion anterograde and collateral flow grades (r = 0.41, p = 0.03 and r = 0.55, p = 0.0004), viability index (r = 0.55, p = 0.04), peak creatine kinase concentrations (r = -0.55, p = 0.0005), left ventricular ejection fraction (r = 0.45, p = 0.005), end diastolic pressure (r = -0.62, p < 0.0001), end systolic volume index (r = -0.47, p = 0.01), and the extent of hypokinetic area (r = -0.48, p = 0.003), but not the coronary flow reserve. On multivariate analysis, independent predictors of late contractility recovery were prereperfusion anterograde and collateral flow grades and viability index. Relative coronary flow reserve, reflecting the culprit vessel's microvascular function, was correlated only to the extent of the infarct risk area (r = -0.45, p = 0.003).

CONCLUSIONS

Independent predictors of contractility recovery between the seventh day and the sixth month after successful stenting for acute myocardial infarction are prereperfusion anterograde and collateral flows and myocardial viability. The culprit vessel's microvascular dysfunction is independent of myocardial viability and contractility and correlated to the extent of "jeopardised microvasculature".