Thrombolysis in Myocardial Infarction frame count in saphenous vein grafts

Angiographic and physiologic assessment of coronary flow and myocardial perfusion in the cardiac catheterization laboratory

INTRODUCTION

For many years, coronary angiography has been used to define coronary artery lesions. Angiographic assessment of coronary flow using the TIMI flow grade system (TFG) and the TIMI frame count (TFC) methods have played a significant role in our understanding of coronary artery disease and they have proved useful in prediction of long-term clinical outcomes after myocardial infarction. The availability of invasive techniques to assess the physiological significance of coronary artery lesions allows a more rationale approach to the management of patients, particularly those with intermediate lesions. The TIMI scores and other angiographic parameters such as the TIMI myocardial perfusion grade (TMPG) are now integrated into clinical practice, as are the use of flow wires and pressure recording wires. Other angiographic techniques, (e.g. digital subtraction angiography), which at this time are predominantly research tools, will require software integration into the imaging chain to facilitate real-time analysis.

CONCLUSION

In this article, we provide a comprehensive descriptive review of the different means of assessment of coronary flow in the cardiac catheterization laboratory, focusing on scores deducted from angiography as well as invasive haemodynamic measurements of blood flow and pressure.

Use of the TIMI frame count in the assessment of coronary artery blood flow and microvascular function over the past 15 years

Since its introduction, the TIMI frame count method has contributed to the understanding of the pathophysiology of coronary artery disease. In this article, the evolution of the TFC method and its applicability in the assessment of various therapeutic modalities are described.

Impact of saphenous vein graft radiographic markers on clinical events and angiographic parameters

BACKGROUND

Use of saphenous vein graft (SVG) radiographic markers has been associated with shorter cardiac catheterization procedure times and reduced contrast agent volume for postoperative coronary artery bypass graft (CABG) catheterizations. Use of such markers is varied and often operator-dependent, as the effect of SVG markers has not been fully evaluated. The goal of the present analysis was to evaluate the association of SVG markers with clinical outcomes and graft patency.

METHODS

Data were drawn from the Project of Ex-vivo Vein Graft Engineering via Transfection (PREVENT) IV trial of patients undergoing CABG at 107 hospitals across the United States. Repeat angiography was performed within 12 to 18 months after CABG. The SVG markers were used at the discretion of the surgeon and were identified on the follow-up angiogram as any device used to mark the ostium, regardless of shape.

RESULTS

The SVG markers were present in 51.2% of evaluable patients (910 of 1,778) and 52.3% of SVGs (2,228 of 4,240). Among patients with totally occluded SVGs (n = 911), visual identification of the SVG was obtained more frequently in those with an SVG marker (90.7% vs 72.1%, p < 0.001). The SVG stenosis 70% or greater at follow-up did not differ by use of markers (25.8% with marker vs 24.4% without marker, p = not significant). These findings were also consistent in ostial lesions (n = 942). Long-term death or myocardial infarction (MI) was similar by use of marker. The perioperative CABG MI was higher in patients with SVG markers (10.1% vs 5.5%, odds ratio adjusted 1.86, p = 0.021).

CONCLUSIONS

Saphenous vein graft radiographic markers were associated with higher rates of direct visualization of totally occluded SVGs without an adverse effect on graft patency or long-term clinical outcomes, but the association of SVG markers with increased perioperative CABG MI warrants further examination.

Filter no reflow during percutaneous coronary interventions using the Filterwire distal protection device

BACKGROUND

Distal protection devices are increasingly used to prevent embolization during percutaneous coronary interventions (PCI) in saphenous vein grafts (SVG) and native coronary arteries (NV). During interventions with the Filterwire device we have observed reduced flow that is reversible following removal of the filter (filter no reflow, FNR), which might be erroneously interpreted as true no reflow and might be associated with reduced capture efficiency of the basket.

METHODS

We analyzed the incidence of FNR in 58 patients (60 lesions) at high risk of embolization undergoing PCI of either a SVG or a NV using the Filterwire (Boston Scientific, Natick, MA). Qualitative and quantitative angiographic analysis was performed, and the volume of collected debris was estimated using a photographic technique.

RESULTS

In our population, about 1/3 of the cases showed FNR, which was associated with angiographically visible filling defects within the basket, indicating macroembolism. However some patients (especially those undergoing vein graft interventions) showed filling defects without FNR, and some others FNR without filling defects. Thus we tried to understand the predictors of FNR: FNR was associated with higher amount of collected debris (36.97 +/- 42.98 mm(3) vs. 11.31 +/- 18.47 mm(3), p = 0.005), was neither prevented by abciximab, nor predicted by high thrombotic burden, increasing stent volume or need for predilatation. When patient with and without angiographically evident macroembolisation were separately analyzed, a linear correlation of FNR with the quantity of debris was only apparent in the macroembolization group.

CONCLUSIONS

Interventionalists should be aware of the "Filter No Reflow", a common but reversible angiographic complication when the Filterwire device is used. Reduced flow seen during these procedures should be treated conservatively. Mechanical obstruction of the filter, but also other mechanisms (pharmacologically active debris? platelet aggregates?) play a role in this phenomenon.

Comparison of flow characteristics and vascular reactivity of radial artery and long saphenous vein grafts [NCT00139399]

Background

The morphological and functional differences between arteries and veins may have implications on coronary artery bypass graft (CABG) survival. Although subjective differences have been observed between radial artery (RA) and long saphenous venous (LSV) grafts, these have not been quantified. This study assessed and compared the flow characteristics and in-vivo graft flow responses of RA and LSV aorto-coronary grafts.

Methods

Angiograms from 52 males taken 3.7 ± 1.0 months after CABG surgery were analyzed using adjusted Thrombolysis in Myocardial Infarction (TIMI) frame count. Graft and target coronary artery dimensions were measured using quantitative coronary angiography. Estimated TIMI velocity (V_E) and volume flow (F_E) were then calculated. A further 7 patients underwent in-vivo graft flow responses assessments to adenosine, acetylcholine and isosorbide dinitrate (ISDN) using intravascular Doppler.

Results

The V_E for RA grafts was significantly greater than LSV grafts (P = 0.002), however there was no difference in volume F_E (P = 0.20). RA grafts showed positive endothelium-dependent and -independent vasodilatation, and LSV grafts showed no statistically significant response to adenosine and acetylcholine. There was no difference in flow velocity or volume responses. Seven RA grafts (11%) had compromised patency (4 (6%) ≥ 50% stenosis in the proximal/distal anastomoses, and 3 (5%) diffuse narrowing). Thirty-seven (95%) LSV grafts achieved perfect patency and 2 (5%) were occluded.

Conclusion

The flow characteristics and flow responses of the RA graft suggest that it is a more physiological conduit than the LSV graft. The clinical relevance of the balance between imperfect patency versus the more physiological vascular function in the RA graft may be revealed by the 5-year angiographic follow-up of this trial.

Mean platelet volume on admission predicts impaired reperfusion and long-term mortality in acute myocardial infarction treated with primary percutaneous coronary intervention

OBJECTIVES

We sought to determine the prognostic value of mean platelet volume (MPV) for angiographic reperfusion and six-month mortality in patients with acute ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI).

BACKGROUND

Mean platelet volume is predictive of unfavorable outcome among survivors of STEMI when measured after the index event. No data are available for the value of admission MPV in patients with STEMI treated with primary PCI.

METHODS

Blood samples for MPV estimation, obtained on admission in 398 consecutive patients presenting with STEMI, were measured before primary PCI. Follow-up up to six months was performed.

RESULTS

No-reflow was significantly more frequent in patients with high MPV (> or =10.3 fl) compared with those with low MPV (<10.3 fl) (21.2% vs. 5.5%, p < 0.0001). The MPV was correlated strongly with corrected Thrombolysis In Myocardial Infarction frame count (CTFC) (r = 0.698, p < 0.0001). Kaplan-Meier survival analysis showed six-month mortality rate of 12.1% in patients with high MPV versus 5.1% in low MPV group (log rank = 6.235, p = 0.0125). After adjusting for baseline characteristics, high MPV remained a strong independent predictor of no-reflow (odds ratio [OR] 4.7, 95% confidence interval [CI] 2.3 to 9.9, p < 0.0001), CTFC > or =40 (OR 10.1, 95% CI 5.7 to 18.1, p < 0.0001), and mortality (OR 3.2, 95% CI 1.1 to 9.3, p = 0.0084). Abciximab administration resulted in significant mortality reduction only in patients with high MPV values (OR 0.02, 95% CI 0.01 to 0.48, p = 0.0165).

CONCLUSIONS

Mean platelet volume is a strong, independent predictor of impaired angiographic reperfusion and six-month mortality in STEMI treated with primary PCI. Apart from prognostic value, admission MPV may also carry further practical, therapeutic implications.

Sequential risk stratification using TIMI risk score and TIMI flow grade among patients treated with fibrinolytic therapy for ST-segment elevation acute myocardial infarction

In the setting of ST-segment elevation myocardial infarction (STEMI), the Thrombolysis In Myocardial Infarction (TIMI) risk score (TRS) and indexes of epicardial and myocardial perfusion are associated with mortality. The association between TRS at presentation and angiographic indexes of epicardial and myocardial perfusion after reperfusion therapy has not been investigated. We hypothesized that TRS, TIMI flow grade (TFG), and TIMI myocardial perfusion grade (TMPG) would provide independent prognostic information and that angiographic indexes of poor flow and perfusion would be associated with a higher TRS. TRS and angiographic data were evaluated in 3,801 patients from the TIMI 4, 10A, 10B, 14, 20, 23, and 24 trials. Within each TRS stratum (TRS 0 to 2, 3 to 4, >/=5), 30-day mortality increased stepwise among patients with impaired TFG at 60 minutes after fibrinolytic administration. In a multivariate model adjusting for the TRS strata, impaired TMPG (0/1) was independently associated with higher mortality (odds ratio 2.28, p = 0.018). In a multivariate model adjusting for the TFG and infarct location, the likelihood of impaired TMPG (0/1) was greater among intermediate-risk (TRS 3 to 4) and high-risk (TRS >/=5) patients than among low-risk (TRS 0 to 2) patients (odds ratio 1.43, p = 0.019 and 1.50, p = 0.055, respectively). Thus, impaired epicardial flow and myocardial perfusion are independently associated with increased 30-day mortality among patients identified by TRS as high risk, although there is no synergism between either TFG or TMPG and TRS. High TRS at presentation is associated with abnormal myocardial perfusion, even after adjusting for possible confounders.

Effect of rescue or adjunctive percutaneous coronary intervention of the culprit artery after fibrinolytic administration on epicardial flow in nonculprit arteries

We hypothesized that blood flow in noninfarct arteries would improve after percutaneous coronary intervention of the culprit artery in the setting of ST-elevation myocardial infarction (STEMI). The corrected Thrombolysis In Myocardial Infarction (TIMI) frame count was measured in 94 patients (102 arteries) enrolled in the INTEGRITI, ENTIRE, and FASTER trials of reduced dose fibrinolytic and glycoprotein IIb/IIIa inhibition. The corrected TIMI frame count in nonculprit arteries improved by 3.4 +/- 13.4 frames after percutaneous coronary intervention but remained significantly slower than flow in normal arteries.

Association of peripheral neutrophilia with adverse angiographic outcomes in ST-elevation myocardial infarction

We hypothesized that absolute and relative neutrophilia would be associated with adverse angiographic outcomes in the 394 patient Limitation of Myocardial Infarction Following Thrombolysis in Acute Myocardial Infarction (LIMIT) Acute Myocardial Infarction (AMI) trial of fibrinolysis in ST-elevation myocardial infarction. The mean neutrophil count was 7.9 x 10(9)/L, with a mean neutrophil percentage of 72%. Patients with time from symptom onset to fibrinolytic treatment more than the median (2.7 hours) had a higher neutrophil count and percentage of neutrophils than patients with shorter time to treatment. Patients with a closed infarct-related artery at 90 minutes (Thrombolysis In Myocardial Infarction [TIMI] grade 0/1 flow) had higher neutrophil counts (8.8 +/- 3.8 vs 7.6 +/- 3.0, p = 0.02) but no difference in the percentage of neutrophils than patients with an open artery. Higher neutrophil counts were also mildly correlated with longer corrected TIMI frame counts (CTFC) in the infarct-related artery (r = 0.14, p = 0.02). Patients with impaired myocardial perfusion by TIMI myocardial perfusion grade (TMPG) had a greater percentage of neutrophils (73.2 +/- 10.7% for TMPG 0/1 vs 69.9 +/- 12.6% for TMPG 2/3, p = 0.047) but no detectable difference in neutrophil counts (8.2 +/- 3.3 vs 7.7 +/- 2.9, p = 0.24). There were no significant associations between other indexes in the cell differential and angiographic or clinical outcomes. Higher neutrophil counts remained independently associated with both closed arteries and CTFC in multivariable models controlling for age, left anterior descending artery infarct location, time to treatment, and pulse and blood pressure on admission. A greater percentage of neutrophils remained independently associated with impaired microvascular perfusion in a similar multivariable model. In patients with ST-elevation myocardial infarction, absolute and relative neutrophilia were associated with impaired epicardial and microvascular perfusion.

Association of creatinine and creatinine clearance on presentation in acute myocardial infarction with subsequent mortality

OBJECTIVES

We hypothesized that impaired renal function would also be associated with poorer clinical outcomes among patients with ST-segment elevation myocardial infarction (STEMI) treated with fibrinolysis.

BACKGROUND

Previous studies have demonstrated that impaired renal function is associated with poorer clinical outcomes in the setting of unstable angina and non-STEMI and after percutaneous coronary intervention.

METHODS

Data were drawn from the Thrombolysis In Myocardial Infarction (TIMI)-10, TIMI-14, and Intravenous nPA for the Treatment of Infarcting Myocardium Early (InTIME-II) trials.

RESULTS

Within each TIMI risk score (TRS) for STEMI category (0 to 2, 3 to 4, >/=5), 30-day mortality increased stepwise among patients with normal (creatinine [Cr] </=1.2 mg/dl), mildly (Cr >1.2 to 2 mg/dl), and severely (Cr >2.0 mg/dl) impaired renal function (p < 0.001) and in patients with normal (creatinine clearance [CrCl] >/=90 ml/min), mildly (60 to <90 ml/min), moderately (30 to <60 ml/min), and severely (<30 ml/min) impaired CrCl (p < 0.001). Impaired renal function was associated with increased mortality after adjusting for previously identified correlates of mortality (using Cr: odds ratio [OR] for mild impairment 1.52, 95% confidence interval [CI] 1.30 to 1.77, p < 0.001; OR for severe impairment 3.73, 95% CI 2.55 to 5.45, p < 0.001; using CrCl: OR for mild impairment 1.38, 95% CI 1.10 to 1.73, p = 0.006; OR for moderate impairment 2.06, 95% CI 1.59 to 2.66, p < 0.001; OR for severe impairment 3.81, 95% CI 2.57 to 5.65, p < 0.001).

CONCLUSIONS

In the setting of STEMI, elevated Cr and/or impaired CrCl on presentation is associated with increased mortality, independent of other conventional risk factors and TRS. This association does not appear to be mediated by reduced fibrinolytic efficacy among patients with impaired renal function or by the presence of congestive heart failure on presentation.

Assessing coronary blood flow dynamics with the TIMI frame count method: comparison with simultaneous intracoronary Doppler and ultrasound

This study compared the TIMI frame count (TFC), which has been proposed as a method for quantifying coronary blood flow, with coronary flow and microvascular function measured with intracoronary Doppler and intracoronary ultrasound. Coronary blood flow volume was calculated from coronary blood velocity (by intracoronary Doppler) and lumen area (by intracoronary ultrasound) in the LAD in 46 post-heart transplant patients at baseline and after intracoronary adenosine. TFC correlated significantly with average peak coronary blood velocity (r = -0.42; P = 0.004) and coronary lumen area (r = 0.39; P = 0.008), but not with coronary blood flow volume (r = -0.01; P = 0.96) or the coronary flow reserve response to adenosine (r = 0.09; P = 0.58). In conclusion, TFC is a simple method of assessing coronary blood velocity but not volumetric flow. While TFC does not predict coronary flow reserve, as a measure of velocity it does provide an assessment of basal microvascular tone, information that is complementary to that afforded by flow reserve measurements.

Impact of contrast agent type (ionic versus nonionic) used for coronary angiography on angiographic, electrocardiographic, and clinical outcomes following thrombolytic administration in acute myocardial infarction

The goal of this study was to examine the relationship between contrast agent type (ionic vs. nonionic) and angiographic, electrocardiographic, and clinical outcomes after thrombolytic administration. Ionic or nonionic contrast agents were selected in a nonrandomized fashion for 90-min angiography and percutaneous coronary intervention (PCI) following thrombolytic administration in the TIMI 14 trial [tissue plasminogen activator (tPA) or reteplase (rPA) vs. low-dose lytic + abciximab]. There was no relationship between contrast agent type and overall patency, rate of TIMI grade 3 flow, or corrected TIMI frame counts (CTFCs) in open culprit arteries and in post-PCI patency rates or post-PCI CTFCs. In patients treated with ionic contrast, ejection fractions at 90 min were slightly but significantly lower (56.2 +/- 16.5, n = 122, vs. 59.8 +/- 14.4, n = 322; P = 0.02), chest pain duration was longer (2.8 +/- 4.1 hr, n = 255, vs. 1.7 +/- 3.6, n = 550; P = 0.0003), and complete ST segment resolution was less frequent (41.5% vs. 50.8%; P = 0.04). While there was no difference in epicardial blood flow, ionic contrast agent use was associated with poorer ST segment resolution, longer chest pain duration, and poorer ejection fractions, perhaps as a result of microvascular dysfunction.

Impact of injections during diagnostic coronary arteriography on coronary patency in the setting of acute myocardial infarction from the TIMI trials. Thrombolysis In Myocardial Infarction

The mechanical force of injection at 90 minutes opens 13.4% of occluded arteries, but overall, only 2.4% of all culprit arteries (already open and occluded combined) are opened. Thus, although some arteries are opened by the force of hand injection, the frequency of mechanical opening among all arteries is low, and hand injections appear to alter current 80% patency rates by approximately 2.5%.

Association between white blood cell count, epicardial blood flow, myocardial perfusion, and clinical outcomes in the setting of acute myocardial infarction: a thrombolysis in myocardial infarction 10 substudy

BACKGROUND

Elevation of the white blood cell (WBC) count during acute myocardial infarction (AMI) is associated with adverse outcomes. We examined the relationship between the WBC count and angiographic findings to gain insight into this relationship. Results and Methods-We evaluated data from 975 patients in the Thrombolysis In Myocardial Infarction (TIMI) 10A and 10B trials. Patients with a closed artery at 60 and 90 minutes had higher a WBC count than patients with an open artery (P:=0.02). Likewise, the presence of angiographically apparent thrombus was associated with a higher WBC count (11.5+/-5.2x10(9)/L, n=290, versus 10.7+/-3. 5x10(9)/L, n=648; P=0.008). In addition, a higher WBC count was associated with poorer TIMI myocardial perfusion grades (4-way P=0.04). Mortality rates were higher in patients with a higher WBC count (0% for WBC count 0 to 5x10(9)/L, 4.9% for WBC count 5 to 10x10(9)/L, 3.8% for WBC count 10 to 15x10(9)/L, 10.4% for WBC count >15x10(9)/L; P=0.03). The development of new congestive heart failure or shock was also associated with a higher WBC count (0% for WBC count 0 to 5x10(9)/L, 5.2% for WBC count 5 to 10x10(9)/L, 6.1% for WBC count 10 to 15x10(9)/L, 17.1% for WBC count >15x10(9)/L; P<0.001), an observation that remained significant in a multivariable model that adjusted for potential confounding variables (odds ratio 1.21, P=0.002).

CONCLUSIONS

Elevation in WBC count was associated with reduced epicardial blood flow and myocardial perfusion, thromboresistance (arteries open later and have a greater thrombus burden), and a higher incidence of new congestive heart failure and death. These observations provide a potential explanation for the higher mortality rate observed among AMI patients with elevated WBC counts and helps explain the growing body of literature that links inflammation and cardiovascular disease.

Prediction of restenosis after coronary angioplasty by use of a new index: TIMI frame count/minimal luminal diameter ratio

BACKGROUND

It has been shown recently that postangioplasty coronary flow reserve and the degree of residual stenosis have a modest predictive value for short- and long-term clinical outcomes after coronary angioplasty. Corrected TIMI frame count (CTFC) is a simple quantitative index of coronary blood flow. Its relationship with Doppler coronary flow velocity and clinical outcome after coronary angioplasty has not been fully clarified. The aim of this study was to identify clinical, angiographic, and functional predictors of clinical and angiographic restenosis after conventional coronary angioplasty.

METHODS AND RESULTS

We studied 70 consecutive patients in whom intracoronary Doppler flow-velocity measurements were performed before and after angioplasty. Patients were evaluated for restenosis by clinical follow-up, exercise stress test/(201)Tl scintigraphy, and follow-up angiography, which was performed at 10. 5+/-10.3 months in 63 patients. According to the results of univariate analysis, a new index, postangioplasty CTFC/minimal luminal diameter (MLD) ratio, was created. Multivariate analysis revealed that CTFC/MLD ratio was the only independent predictor of angiographic (OR 2.02; 95% CI 1.37 to 2.97; P<0.0004) and clinical (OR 1.60; 95% CI 1.15 to 2.21; P<0.005) restenosis. The receiver operating characteristic curve area of this index was 79% for angiographic and 73% for clinical restenosis. The optimal CTFC/MLD ratio cutoff values were 7.88 for angiographic and 7.94 for clinical restenosis, respectively.

CONCLUSIONS

Our data indicate that postangioplasty CTFC/MLD ratio, which incorporates both the angiographic and functional features of coronary lesions, is a reliable, objective, and inexpensive index for prediction of angiographic and clinical restenosis after conventional coronary angioplasty.

Weight-adjusted dosing of TNK-tissue plasminogen activator and its relation to angiographic outcomes in the thrombolysis in myocardial infarction 10B trial. TIMI 10B Investigators

Fixed doses of thrombolytic agents are generally administered to patients of varying body weights, and the dose-response relation may be confounded by the variability in patient weight. We hypothesized that higher doses of TNK-tissue plasminogen activator (tPA) per unit body weight would be related to improved flow at 90 minutes after thrombolytic administration. A total of 886 patients with acute myocardial infarction were randomized to receive either a single bolus of 30, 40, or 50 mg of TNK-tPA or front-loaded tPA in the Thrombolysis In Myocardial Infarction (TIMI) 10B trial. The dose of TNK-tPA administered was divided by the patient's weight to arrive at the TNK-tPA dose (mg) per unit body weight (kg), and patients were stratified into tertiles based on mg/kg of TNK-tPA: low dose, 0.2 to 0.39 mg/kg; mid-dose, 0.40 to 0.51 mg/kg; high dose, 0.52 to 1.24 mg/kg. Flow in the culprit and nonculprit arteries was analyzed using the TIMI flow grades and the corrected TIMI frame count (CTFC). The median CTFC in culprit arteries differed between the tertiles (3-way p = 0.007), with the CTFC being 7.2 frames faster in high-dose than in low-dose patients (43.1 +/- 30.1, median 31.2, n = 171 vs 54.6 +/- 34.8, median 38.4, n = 166, 2-way p = 0.002). Patients in the mid- and high-dose tertiles achieved patency more frequently (TIMI grade 2 or 3 flow) by 60 minutes (p = 0.02), and the 90-minute percent diameter stenosis was less severe in patients in the high- versus low-dose tertile (p = 0.03). In nonculprit arteries, the CTFC was faster in high- than in low-dose tertiles (29.6 +/- 13.4, median 26.9, n = 130 vs 34.7 +/- 16.3, median 32.8, n = 108, 3-way p = 0.03, 2-way p = 0.008). In patients who underwent percutaneous transluminal coronary angioplasty (PTCA), the CTFC in culprit arteries after PTCA was fastest in the high- and mid-dose tertiles than in those receiving low doses (2-way p = 0.05). Thus, higher doses per unit body weight of TNK-tPA result in not only faster culprit artery flow, but also faster nonculprit, global, and post-PTCA flow, which may reflect earlier opening, reduced stunning, or improved microvascular function. The greater effectiveness of thrombolysis must be weighed against any increase in risk.