Clinical outcome of deferring angioplasty in patients with normal translesional pressure-flow velocity measurements.

OBJECTIVES: The objective of this study was to determine the feasibility, safety and outcome of deferring angioplasty in patients with angiographically intermediate lesions that are found not to limit flow, as determined by direct translesional hemodynamic assessment. BACKGROUND: The clinical importance of some coronary stenoses of intermediate angiographic severity frequently requires noninvasive stress testing. Direct translesional pressure and flow measurements may assist in clinical decision making in patients with such stenoses. METHODS: Translesional spectral flow velocity (Doppler guide wire) and pressure data were obtained in 88 patients for 100 lesions (26 single-vessel and 74 multivessel coronary artery lesions) with quantitative angiographic coronary narrowings (mean +/- SD diameter narrowing 54 +/- 7% [range 40% to 74%]). Target lesion angioplasty was prospectively deferred on the basis of predetermined normal values, defined as a proximal/distal velocity ratio < 1.7 or a pressure gradient < 25 mm Hg, or both. Patients were followed up for 9 +/- 5 months (range 6 to 30). RESULTS: In the deferred angioplasty group, translesional velocity ratios were similar to those of a normal reference group (mean 1.1 +/- 0.32 vs. 1.3 +/- 0.55) and significantly lower than those of a reference cohort of patients who had undergone angioplasty (2.27 +/- 1.2, p < 0.05). The mean translesional pressure gradient in the deferred angioplasty group was also lower than that in the angioplasty group (10 +/- 9 vs. 45 +/- 22 mm Hg, p < 0.001). At follow-up in the deferred angioplasty group, four, six, zero and two patients, respectively, had had subsequent angioplasty, coronary artery bypass graft surgery or myocardial infarction or had died. In one patient, death was related to angioplasty of a nontarget artery lesion, and one patient with multivessel disease had a cardiac arrest due to ventricular fibrillation 12 months after lesion assessment. Among the 10 patients requiring later angioplasty or coronary artery bypass grafting, only six procedures were performed on target arteries. No patient had a complication of translesional flow or pressure measurements. CONCLUSIONS: These data demonstrate the safety, feasibility and clinical outcome of deferring angioplasty of coronary artery narrowings associated with normal translesional coronary hemodynamic variables. Given the practice of performing angioplasty without ischemic testing or when testing is inconclusive, translesional hemodynamic data obtained at diagnostic catheterization can identify patients in whom it is safe to postpone angioplasty.

Variations in normal coronary vasodilatory reserve stratified by artery, gender, heart transplantation and coronary artery disease.

OBJECTIVES: The purpose of the study was to assess the spectrum of coronary vasodilatory reserve values in patients with angiographically normal arteries who had atypical chest pain syndromes or remote coronary artery disease or were heart transplant recipients. BACKGROUND: The measurement of post-stenotic coronary vasodilatory reserve, now possible in a large number of patients in the cardiac catheterization laboratory, is increasingly used for decision making. Controversy exists regarding the range of normal values obtained in angiographically normal coronary arteries in patients with different clinical presentations. METHODS: Quantitative coronary arteriography was performed in 214 patients classified into three groups: 85 patients with chest pain syndromes and angiographically normal arteries (group 1); 21 patients with one normal vessel and at least one vessel with > 50% diameter lumen narrowing (group 2); and 108 heart transplant recipients (group 3). Coronary vasodilatory reserve (the ratio of maximal to basal average coronary flow velocity) was measured in 416 arteries using a 0.018-in. (0.04 cm) Doppler-tipped angioplasty guide wire. Intracoronary adenosine (8 to 18 micrograms) was used to produce maximal hyperemia. RESULTS: Coronary vasodilatory reserve was higher in angiographically normal arteries in patients with chest pain syndromes (group 1:2.80 +/- 0.6 [group mean +/- SD]) than in normal vessels in patients with remote coronary artery disease (group 2: 2.5 +/- 0.95, p = 0.04); both values were significantly higher than those in the post-stenotic segment of the diseased artery (1.8 +/- 0.6, p < 0.007). Coronary vasodilatory reserve in transplant recipients (group 3) was higher than that in the other groups (3.1 +/- 0.9, p < 0.05 vs. groups 1 and 2) as a group and for individual arteries. When stratified by vessel, coronary vasodilatory reserve was similar among the left anterior descending, left circumflex and right coronary arteries. There were no differences between coronary vasodilatory reserve values on the basis of gender for patients with coronary artery disease and transplant recipients. In group 1 (chest pain), there was a trend toward higher coronary vasodilatory reserve in men than in women (2.9 +/- 0.6 vs 2.7 +/- 0.6, p = 0.07). CONCLUSIONS: These findings identify a normal reference range for studies assessing the coronary circulation and post-stenotic coronary vasodilatory reserve in patients with and without coronary artery disease encountered in the cardiac catheterization laboratory.

Role of coronary artery lumen enlargement in improving coronary blood flow after balloon angioplasty and stenting: a combined intravascular ultrasound Doppler flow and imaging study.

OBJECTIVES: This study sought to examine the mechanism of increasing coronary flow reserve after balloon angioplasty and stenting. BACKGROUND: Coronary vasodilatory reserve (CVR) does not improve after percutaneous transluminal coronary angioplasty in > or = 50% of patients, postulated to be due to impaired microvascular circulation or inadequate lumen expansion despite adequate angiographic results. METHODS: To demonstrate the role of coronary lumen expansion, serial coronary flow velocity (0.014-in. Doppler guide wire) was measured in 42 patients before and after balloon angioplasty and again after stent placement. A subset (n = 17) also underwent intravascular ultrasound (IVUS) imaging of the target sites after angioplasty and stenting. CVR (velocity) was computed as the ratio of adenosine-induced maximal hyperemic to basal average peak velocity. RESULTS: The percent diameter stenosis decreased from (mean +/- SD) 84 +/- 13% to 37 +/- 18% after angioplasty and to 8 +/- 8% after stenting (both p < 0.05). CVR was minimally changed from 1.70 +/- 0.79 at baseline to 1.89 +/- 0.56 (p = NS) after angioplasty but increased to 2.49 +/- 0.68 after stent placement (p < 0.01 vs. before and after angioplasty). IVUS lumen cross-sectional area was significantly larger after stenting than after angioplasty (8.39 +/- 2.09 vs. 5.10 +/- 2.03 mm2, p < 0.05). Anatomic variables were related to increasing coronary flow velocity reserve (CVR vs. IVUS lumen area: r = 0.47, p < 0.005; CVR vs. quantitative coronary angiographic percent area stenosis: r = 0.58, p < 0.0001). CONCLUSIONS: In most cases, increases in CVR were associated with increases in coronary lumen cross-sectional area. These data suggest that impaired CVR after angioplasty is often related to the degree of residual narrowing, which at times may not be appreciated by angiography. A physiologically complemented approach to balloon angioplasty may improve procedural outcome.

Assessment of angiographically intermediate coronary artery stenosis using the Doppler flowire.

Determination of the clinical and hemodynamic significance of coronary stenoses is often difficult and inexact. Angiography and coronary vasodilator reserve have been shown to be imperfect tools to determine the physiologic significance of coronary stenoses. Spectral flow velocity data, both proximal and distal to coronary stenoses, using an 0.018-in intracoronary Doppler-tipped angioplasty guidewire, were compared to translesional pressure gradients and angiography during cardiac catheterization. Patients were divided into 2 groups based on resting translesional gradients: Group 1 had gradients < 20 mm Hg and group 2 had gradients > or = 20 mm Hg. Proximal average peak velocity, diastolic velocity integral, and total velocity integral were statistically significantly lower in Group 1. The distal average peak velocity, and diastolic and total velocity integrals were all significantly (p < 0.01) decreased in patients with gradients > 20 mm Hg (group 2). The ratio of proximal-to-distal total flow velocity integral was also higher in group 2 patients (2.3 +/- 0.9) compared with group 1 (1.1 +/- 0.2; p < 0.001). There was a strong correlation between translesional pressure gradients and the ratios of the proximal-to-distal total flow velocity integrals (r = 0.8, p < 0.001) with a weaker relationship between quantitative angiography and pressure gradients (r = 0.6, p < 0.001). Angiography was a poor predictor of translesional gradients in angiographically intermediate stenoses (range 50-70%; r = 0.2, p = NS), while the flow velocity ratios continued to have a strong correlation (r = 0.8, p < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitating coronary collateral flow velocity in patients during coronary angioplasty using a Doppler guidewire.

Quantitation of coronary collateral flow in patients has been limited to angiographic techniques, which are subject to well-known methodologic limitations. The use of a Doppler-tipped angioplasty guidewire permits measurement of both antegrade and retrograde flow distal to totally or subtotally occluded vessels that may be supplied with acutely recruitable or angiographically mature collateral conduits. Using coronary flow velocity as an indicator of collateral flow, retrograde flow velocity was quantitated in 17 patients. Mean collateral flow velocity was approximately 30% of normal postangioplasty antegrade flow velocity. The phasic pattern of collateral flow was highly variable, but the retrograde diastolic and systolic flow velocity integrals were 20% and 40% (respectively) of post-procedure antegrade flow velocity. Preliminary studies with pharmacologic stimulation of the contralateral supply artery suggests that collateral flow is not increased by intracoronary nitroglycerin (200 micrograms) or adenosine (12 micrograms), but may be markedly augmented during mechanical stimulation of balloon occlusion. These data represent the first in a series of quantitative observations on control of the coronary collateral circulation in humans. Future investigations using the Doppler Flowire (Cardiometrics) will enhance understanding of factors modulating ischemia through collateral supply.

Comparison of quantitative angiographically derived and measured translesion pressure and flow velocity in coronary artery disease.

Although quantitative coronary angiography (QCA) has been used to determine lesion severity, angiographically derived parameters of translesional physiology have not been compared with those directly measured in the same patients. Thus, the aim of this study was to correlate QCA-derived translesional pressure and flow data with directly measured data in patients. QCA (DCI-ACA program), translesional pressure gradient (2.2Fr fluid-filled tracking catheter), and intracoronary Doppler flow velocity (0.018-inch FloWire) measurements were simultaneously performed in 28 arteries (25 patients). Mean diameter stenosis was 51 +/- 2.3% (range 29 to 73). No patient had left ventricular hypertrophy or valvular heart disease. The arteries studied were left anterior descending in 14, circumflex in 8, and right coronary in 6 patients. Stenotic flow reserve and baseline and maximal gradients were calculated by the DCI program. Coronary flow reserve and baseline and maximal hyperemic gradients were also directly measured distal to the stenosis after administration of intracoronary adenosine (12 to 18 micrograms). QCA-derived pressure gradients did not correlate with the measured gradients at baseline (r2 = 0.005; p = 0.73) or at maximal hyperemia (r2 = 0.1; p = 0.13). No correlation was found between the QCA-predicted flow reserve and the coronary flow reserve measured distal to the stenosis (r2 = 0.02; p = 0.46). Furthermore, stenotic flow reserve and measured gradient were not significantly correlated (r2 = 0.1; p = 0.16). In this range of stenoses of intermediate severity, there was no correlation between the measured pressure gradient or coronary flow reserve and lesion diameter or cross-sectional area by QCA.(ABSTRACT TRUNCATED AT 400 WORDS)

Correlation of poststenotic hyperemic coronary flow velocity and pressure with abnormal stress myocardial perfusion imaging in coronary artery disease.

The functional significance of coronary stenoses is frequently determined by adjunctive noninvasive myocardial perfusion imaging. Poststenotic coronary flow velocity and pressure can be measured directly during routine cardiac catheterization. The aim of this study was to correlate poststenotic (distal) flow velocity and pressure with stress perfusion imaging in patients. Quantitative angiography, basal and hyperemic transstenotic coronary flow velocities, and pressure gradients were measured in 50 patients within 1 week of exercise (n = 29) or of pharmacologic (n = 21) stress perfusion imaging. Twenty-two of 25 patients (88%) with reversible perfusion abnormalities had diminished distal coronary flow velocity reserves (CFVR) of < or = 2.0 x baseline, whereas 22 of 25 (88%) with normal perfusion imaging studies had a normal distal CFVR of > 2.0 (p = 0.000 1). Thirteen of 25 patients (52%) with reversible perfusion abnormalities had transstenotic gradients > or = 20 mm Hg, whereas 20 of 25 (80%) with normal perfusion studies had gradients <20 mm Hg (p = 0.01). Quantitative angiography did not differentiate patients with normal versus abnormal myocardial perfusion imaging. Distal CFVR was correlated more significantly with myocardial perfusion imaging results (kappa = 0.76) than with pressure gradients (kappa = 0.32). Exercise and pharmacologic stress myocardial perfusion imaging abnormalities reflect diminished post-stenotic coronary flow to a greater degree than transstenotic pressure gradients.

Collateral flow velocity alterations in the supply and receiving coronary arteries during angioplasty for total coronary occlusion.

The unique observations of contralateral and ipsilateral coronary artery collateral supply before and after angioplasty suggest highly responsive conduits to hemodynamic conditions. The study of collateral supply system is not only significant for our current understanding of the dynamic behavior of the collateral circulation, but may also have important clinical implications for the treatment of patients with a chronic coronary occlusion.

Limitations of translesional pressure and flow velocity for long ostial left anterior descending stenoses.

Translesional pressure and flow velocity can be used to assess angiographically intermediate or indeterminate lesions. Ostial narrowings and long lesions represent situations that may require both pressure and flow velocity assessment. In patients with hypertension, diabetes mellitus, and chronic renal failure, distally measured absolute and regional coronary reserve values alone may not be helpful in selecting lesions requiring intervention.

Coronary stenoses with low translesional gradient and abnormal coronary reserve: physiologic results after angioplasty.

Clinically active but angiographically moderate coronary stenoses present a difficult problem for intervention, especially when such lesions have a low translesional pressure gradient and impaired coronary reserve. Physiologic data suggest some lesions can be safely deferred, whereas others may benefit from immediate intervention.

Translesional pressure-flow velocity assessment in patients: Part I.

Interventional physiology presents the operator with objective data to facilitate decision making. A thorough and validated understanding of the alterations of pressure and flow in the human coronary circulation is currently in progress. As illustrated in the case studies, some situations have data which may initially appear contradictory or unhelpful to clinical practice. These data should provide a framework to understand the dynamic physiology producing the clinical syndromes in patients undergoing coronary interventional procedures. Future Interventional Physiology Rounds will examine coronary pressure-flow responses during directional atherectomy, stents, and acute myocardial infarction.

Conservative management of guidewire coronary artery perforation with pericardial effusion during angioplasty for acute inferior myocardial infarction.

A wire perforation of a totally occluded right coronary artery was treated successfully with prolonged balloon inflation. This non-surgical management is preferred if physiologic and anatomic conditions are suitable.

Comparison of phasic blood flow velocity characteristics of arterial and venous coronary artery bypass conduits.

BACKGROUND: Coronary artery bypass conduits derived from internal mammary arteries show relative resistance to atherosclerosis and significantly improved long-term patency compared with saphenous vein grafts. Atherothrombotic occlusion of venous conduits has previously been correlated with lower flow rates measured intraoperatively. To quantitate coronary bypass conduit flow velocity, we examined the phasic blood flow velocity patterns by intravascular Doppler spectral analysis in patients during cardiac catheterization to test the hypothesis that resting systolic and diastolic phasic blood flow velocity patterns differ significantly between arterial and venous bypass conduits. METHODS AND RESULTS: Spectral phasic blood flow velocity was measured using an intravascular Doppler-tipped angioplasty guidewire in the proximal, mid, and distal segments of 18 internal mammary artery conduits and 11 saphenous vein grafts in 27 patients at a mean of 4 years (range, 1 to 11) postoperatively. In situ internal mammary artery conduits demonstrated a gradual longitudinal transition in the phasic flow pattern from predominantly systolic velocity proximally (diastolic/systolic peak velocity ratio, 0.6 +/- 0.2) to predominantly diastolic velocity distally (diastolic/systolic peak velocity ratio, 1.4 +/- 0.3; P < .001). Saphenous vein graft flow velocity pattern, however, showed a consistently diastolic predominance, both proximally and distally (diastolic/systolic peak ratios, 1.4 +/- 0.6 and 1.5 +/- 0.7, respectively; P = NS). Mean flow velocities, total velocity integral, and calculated maximal shear rates were significantly higher in all segments of internal mammary arteries compared with values in saphenous vein grafts. CONCLUSIONS: Patterns of resting phasic blood flow, as well as mean velocity and total velocity integral, differ significantly between internal mammary artery and saphenous vein bypass conduits. These differences may have implications regarding blood-vessel wall interactions, the development of degenerative graft disease, and long-term conduit patency.

Approach to total occlusion of an aorto-ostial "Y" saphenous vein graft with anterior descending graft limb stenosis by serial balloon angioplasty and elective stent deployment.

Coronary revascularization using balloon angioplasty and stent placement for unstable angina was performed in a 74-year-old woman with an aorto-ostial occlusion of a "Y-type" saphenous vein graft and a severe stenosis in the body of a 14-year-old left anterior descending saphenous vein graft. Multiple prior coronary bypass graft surgeries, location of branch graft lesions, and length of the ostial stenosis must be considered in selecting the approach to revascularization.

Application of intracoronary flow velocity for detection and management of ostial saphenous vein graft lesions.

Ostial lesions of saphenous vein grafts can be difficult to assess by angiography. A physiologic approach to the selection and recanalization of ostial lesions in saphenous vein grafts may be advantageous to overcome limitations of angiography. To assist in identifying favorable physiology and facilitate procedural decision making, the use of coronary flow velocity measurements with a Doppler-tipped 0.018-inch angioplasty flowire in three particularly difficult patients with varying types of saphenous vein graft aorto-ostial narrowings is reported.

Use of translesional coronary flow velocity for interventional decisions in a patient with multiple intermediately severe coronary stenoses.

Translesional pressure gradients are currently not performed routinely for most angioplasty procedures because of the technical limitations. With the use of an 0.18 inch Doppler flow velocity guidewire, coronary flow velocity, both proximal and distal to a lesion, can be easily assessed. In branching arteries, significant lesions are characterized by a ratio of proximal to distal flow velocity of > 1.7, loss of the normal phasic diastolic predominant flow velocity pattern, and/or loss of distal hyperemia. We describe the use of coronary flow velocity in assisting important decision making in a young patient with a recent myocardial infarction and multiple coronary lesions. The decision for angioplasty of the hemodynamically significant stenosis was confirmed by translesional flow velocity measurements. A rational approach to coronary intervention in patients with multiple stenoses of intermediate severity appears to be facilitated by direct measurement of translesional flow dynamics.

Quantification of collateral blood flow during PTCA by intravascular Doppler.

The assessment of flow velocity using the Doppler guidewire provides a means of investigating both antegrade and retrograde blood flow in the coronary artery distal to obstructive lesions and occluding PTCA balloons. This has yielded unique qualitative and quantitative information regarding coronary collateral blood flow, and the responses of collaterals to pharmacological and haemodynamic perturbations. The current study analysed collateral flow velocity recordings obtained during coronary interventions in 46 patients in our laboratory. The mean collateral peak velocity integral distal to the occluding PTCA balloon was 9 +/- 7 units, while antegrade distal coronary peak velocity integral following stenosis relief by PTCA was 27 +/- 12 units. Thus, during PTCA balloon occlusion collaterals were able to supply a mean of 30 +/- 18% of the flow provided antegrade by successful PTCA. Variability in collateral flow velocity was not accounted for by differences in the PTCA artery assessed, the supply artery, the direction of collateral filling, the severity of coronary stenosis, or the angiographic grade of collaterals, and the magnitude of collateral flow velocity did not correlate with preserved left ventricular regional wall motion. The measurement of collateral flow velocity by intravascular Doppler provides unique and quantitative information regarding the coronary collateral circulation.

Alterations of coronary flow velocity during intervention for acute myocardial infarction: responses to complications of intracoronary thrombolysis and angioplasty.

Alterations, either an increase or decrease, in the distal flow velocity over time are associated with alterations in vessel diameter and/or unstable flow velocity. Unexplained unstable flow velocity patterns should act as early warning signs to prompt the interventionalist to assess continued coronary patency and need for renewed interventions.

Comparison of surgical and medical group survival in patients with left main equivalent coronary artery disease. Long-term CASS experience.

BACKGROUND: Combined severe proximal left anterior descending and proximal left circumflex coronary artery disease, or left main equivalent (LMEQ) disease, defines a prognostic high-risk angiographic subset of patients with chronic ischemic heart disease. While numerous observational and randomized clinical trials showed prolonged survival in surgically compared with medically treated patients with left main coronary artery disease, relatively few observational studies compared surgical and medical therapies in patients with LMEQ disease. The present report of 912 patients with LMEQ disease in the Coronary Artery Surgery Study (CASS) Registry extends the originally published 5-year surgical and medical group survival analysis to more than 16 years of follow-up and permits analysis of LMEQ patient subgroups. METHODS AND RESULTS: The CASS Registry contains 912 patients with LMEQ disease, defined as combined stenoses of > or = 70% in the proximal left anterior descending coronary artery before the first septal perforator and proximal circumflex coronary artery before the first obtuse marginal branch, initially treated with either surgical or nonsurgical therapy. The 15-year cumulative survival estimates were 44% for the 630 patients in the surgical group and 31% for the 282 patients in the medical group. Median survival in the surgical group was 13.1 years (12.7 to 14.1 years, 95% confidence limits) compared with only 6.2 years (4.8 to 7.9 years) in the medical group (difference, 6.9 years; P < .0001). Median survival was also significantly longer in the surgical group stratified by age, sex, anginal class, left ventricular (LV) function, and coronary anatomy. However, coronary artery bypass graft (CABG) surgery did not significantly prolong median survival in patient subgroups with (1) normal LV systolic function, even if a significant right coronary artery stenosis (> or = 70%) also was present, and (2) mildly abnormal (LV score, 6 to 10) LV systolic function. The 15-year cumulative survival in patients with normal LV systolic function in the surgical and medical groups was 63% and 54%, respectively. Median survival was > 15 years in both the surgical and medical groups (P = NS). In patients with normal LV systolic function and right coronary artery stenosis > or = 70%, the 15-year cumulative survival was also similar in the surgical and medical groups (63% and 53%, respectively). Median survival was > 15 years in both the surgical and medical groups (P = NS). The 15-year cumulative survival estimates in all subgroups were affected by convergence of the surgical and medical group survival curves caused by a disproportionate increase in late surgical group mortality. Overall, 26% of patients in the medical group ultimately underwent CABG surgery. If all medical group patients had survived long enough, about 65% would be estimated to have had surgery by 15 years. When the CASS Registry patients with LMEQ disease who participated in the randomized trial or who were randomizable were analyzed, CABG surgery did not prolong the 15-year cumulative survival estimates compared with nonsurgical therapy for randomized (71% versus 67%, respectively) and for randomizable patients (62% versus 92%, respectively) with an LV ejection fraction > or = 50%. CONCLUSIONS: This report, which extends follow-up of more than 16 years in CASS Registry patients with LMEQ disease, shows that CABG surgery prolongs life in most clinical and angiographic subgroups. However, median survival was not prolonged by CABG surgery in patients with normal LV systolic function, even if a significant right coronary artery stenosis (> or = 70%) also was present or in patients with an LV ejection fraction > or = 50% who participated in the CASS randomized trial or who were randomizable.