心肌桥对冠状动脉血流储备的影响

目的　探讨心肌桥对冠状动脉血流储备的影响。方法　对 16例经冠状动脉造影诊断有心肌桥者作冠状动脉内多普勒检查 ,观察并记录壁冠状动脉及其远近段血流图形及特点 ,壁冠状动脉远段、近段的基础平均峰值流速 (bAPV)和充血平均峰值流速 (hAPV) ,分别计算出壁冠状动脉远段、近段的血流储备 (CFR)并予比较 ,作配对t检验。CFR定义为冠状动脉相同节段hAPV和bAPV的比值。结果　 16例患者的心肌桥均位于左前降支 ,其壁冠状动脉多普勒频谱血流图形呈特征性的舒张早期指尖样变化 ,壁冠状动脉近段和远段bAPV无明显差异 [(18 8± 9 2 )cm/s比 (17 5± 7 8)cm/s,P>0 0 5 ],而hAPV的增加明显高于其远段 [(5 5 5± 19 5 )cm/s比 (4 1 1± 17 9)cm/s,P <0 0 5 ]。壁冠状动脉近段CFR明显高于其远段 (3 13± 1 15比 2 38± 0 76 ,P <0 0 1)。结论　心肌桥使壁冠状动脉的多普勒血流图形呈特征性指尖样现象 ,其远段CFR下降 ,低于其近段值     

多巴酚丁胺对心肌桥-壁冠状动脉血流动力学的作用

目的探讨运动对心肌桥患者血流动力学的影响。方法观察8例心肌桥患者在静脉滴注多巴酚丁胺前后壁冠状动脉受压程度的变化,并运用腔内多普勒技术观察壁冠状动脉的基础峰值血流速率(bAPV)、最大峰值血流速率(hAPV)、冠状动脉血流储备(CFR)的变化。结果多巴酚丁胺使壁冠状动脉受压程度由用药前的平均(51.7±21.4)%增加至(90.0±12.7)%,P<0.01;壁冠状动脉近段和远段的 hAPV 分别由(19.83±5.84)cm/s 和(20.75±4.91)cm/s 增加至(31.52±10.93)cm/s 和(30.46±9.01)cm/s;壁冠状动脉近段和远段的 CFR 分别由(2.91±0.62和2.46±0.82,P<0.05)下降至(2.17±0.66和1.83±0.51,P 均<0.01)。结论运动可能使壁冠状动脉受压程度增加,CFR 显著下降。     

冠状动脉内多普勒血流测定在冠状动脉造影正常者中的应用价值

目的　本研究旨在通过对有胸痛但冠状动脉造影正常者行冠状动脉内多普勒血流速度测定 ,评价这组病人的冠状动脉血流储备功能及其影响因素。方法　对 12 6例冠状动脉造影正常而获得满意血流频谱病人 [男 6 7例 ,女 5 9例 ,平均年龄 (5 3 1± 13 0 )岁 ],采用冠状动脉内多普勒血流速度描记技术对左前降支进行血流速度测定 ,并经冠状动脉内注射腺苷 18μg后测定冠状动脉血流速度储备 (CFVR)。结果　 12 6例病人的左前降支的CFVR平均值为 2 71± 0 74,基础冠状动脉平均峰值血流速度 (bAPV)为 (18 7± 7 2 )cm s,充血相平均峰值血流速度 (hAPV)为 (47 7± 15 2 )cm s。其中6 5 1%的病人CFVR低于 3 0 ,与CFVR正常者 (≥ 3 0 )相比 ,这组病人的bAPV较高而hAPV较低。CFVR与基础心率成负性直线相关 (r=- 0 34 8,P <0 0 0 1) ,而bAPV与基础心率呈正性直线相关 (r =0 376 ,P <0 0 0 1)。CFVR和bAPV与血压均无明显相关关系。有无高血压及高脂血症对CFVR无明显影响。糖尿病患者的CFVR低于无糖尿病的患者 (2 30± 0 47vs 2 80± 0 6 8,P =0 0 44 )。结论　有胸痛但冠状动脉造影正常的病人中约 2 3存在微血管功能障碍 ,冠状动脉血流储备功能受心率的影响 ,糖尿病患者的冠状动脉血流储备功能降低     

弹丸注射三磷腺苷对冠状动脉血流的影响

目的　研究静脉弹丸注射三磷腺苷 (ATP)对冠状动脉血流的影响和临床意义。方法　 38例高血压病和心电图心肌缺血者接受经食管多普勒超声检查 ,测定和比较静脉弹丸注射 2 0 m g三磷腺苷与静脉缓慢注射 0 .84 m g/ kg潘生丁后的冠状动脉血流速度和血流储备 (CFR) ;结果　注射 ATP后冠状动脉舒张期峰值和平均血流速度分别为 (114 .0± 4 2 .9) cm/ s和 (84 .6± 33.4 ) cm / s ,CFR分别为 2 .7± 0 .8和 2 .6± 0 .8,略大于注射潘生丁后的相应值(111.3± 37.7) cm/ s和 (83.0± 32 .6 ) cm/ s及 2 .6± 0 .7和 2 .5± 0 .7,无显著差异 ,上述相应测值之间呈高度和中高度相关 (r=0 .919,0 .90 4 ,0 .5 99和 0 .6 0 0 ) ,静脉弹丸注射 ATP测定 CFR仅需 3min,而静脉缓慢注射潘生丁测定CFR需 13m in。结论　冠状动脉血流储备测定中静脉弹丸注射 ATP临床应用价值优于潘生丁。     

微血管性心绞痛冠状动脉血流速度与内皮损伤的研究

目的　通过冠状动脉血流多普勒检测 ,探讨微血管病变患者的冠状动脉血流速度及其与血管内皮损伤、局部微血栓的关系。方法　对有胸痛而冠状动脉造影正常的 16例患者的 43支血管 (右冠状动脉 14支 ,左前降支 15支 ,左回旋支 14支 )行冠状动脉内多普勒超声血流检查 ,记录基础血流参数和充血相血流参数 ,同时记录冠状动脉血流速率储备 (CFVR)。以CFVR 2 5为标准 ,分为正常组 (A组 )和微血管病变组 (B组 ) ,比较二组的冠状动脉血流速度参数及血浆血管性假血友病因子(vWF)的差异。结果　A组包括 7例患者的 19支血管 ,B组包括 9例患者的 2 4支血管。A组的基础平均峰值流速 (bAPV)显著小于B组 [(17 7± 4 8)vs (2 0 9± 5 4)cm s ,P <0 0 0 1];而充血相平均峰值流速 (hAPV)A组显著大于B组 [(5 1 0± 13 3)vs (4 2 5± 11 3)cm s ,P <0 0 5 ];A组的CFVR显著大于B组 [(2 9± 0 5 )vs (2 0± 0 3) ,P <0 0 0 1];A组的血浆vWF显著小于B组 [(112 5± 2 7 5 ) %vs(173 2± 40 8) % ,P <0 0 5 ]。结论　微血管病变患者的基础平均峰血流速度显著增大 ,而充血相平均峰血流速度显著减小 ,可能与冠状动脉内皮损伤及局部微血栓形成有关。     

胸痛患者冠状动脉血流储备的超声研究

目的 :应用多平面经食管多普勒超声心动图 (TEE)潘生丁负荷试验 ,探讨胸痛患者的冠状动脉 (冠脉 )循环特点及血流储备 (CFR)功能。方法 :将受试者分为 4组 :冠脉前降支重度狭窄 (A组 ) 10例 ,轻度狭窄 (B组 ) 6例 ,X综合征 (C组 ) 7例 ,冠脉造影正常 (对照组 ) 15例。应用TEE测定冠脉前降支血流频谱 ,以基础状态下(R)和潘生丁负荷后 (D)冠脉舒张期最大流速比值 (D/RPDV)为CFR的指标。结果 :与对照组比较 ,其他 3组基础状态时冠脉血流速度差异无显著性意义 ;CFR明显减低 ,以A组最为明显〔(1.5 5± 4 3)∶(3.4 3± 0 .6 2 )cm/s,P<0 .0 0 1〕 ,狭窄程度与D/RPDV高度相关 (r =0 .83,P <0 .0 0 1) ;B组与C组比较 ,CFR减低程度一致〔(2 .6 2± 0 .71)∶(2 .19± 0 .36 )cm/s,P >0 .0 5 )〕。结论 :CFR反映了冠脉狭窄时冠脉的血流动力学改变 ,可用于判断冠脉狭窄的程度 ;CFR减低是冠脉造影正常患者胸痛的原因     

应用血管内多普勒超声评价主动脉瓣返流对冠状动脉血流的影响

目的应用血管内多普勒超声评价主动脉瓣返流对冠状动脉血流的影响。方法选取慢性重度的主动脉瓣返流患者12例,先行冠状动脉造影检查,排除冠心病,再行冠状动脉内多普勒检查,测定前降支中远端的平均峰值流速(APV),舒张收缩流速比值(DSVR),冠状动脉血流储备(CFR)等,并测定左心室舒张末压力(LVEDP),用12例正常数据作对照。结果与正常对照相比,主动脉瓣返流患者 APV 升高[(45.8±19.5)cm/s vs.(23.5±15.4)cm/s,P<0.05];DSVR 降低[(1.4±0.8)vs.(2.6±1.7),P<0.05];CFR 降低[(1.5±1.9)cm/s vs.(3.8±2.1)cm/s,P<0.05];LVEDP 升高[(20.6±10.5)mm Hg(1 mm Hg=0.133 kPa)vs.(8.2±5.6)mm Hg,P<0.05];前降支中段内径无变化[(3.8±1.5)mm us.(3.5±1_4)mm,P>0.05]。结论慢性重度主动脉瓣返流对冠状动脉血流有显著影响,表现为基础状态时 APV 升高,而 DSVR 和 CFR 降低,并使左心室舒张功能减低。CFR减低可能是冠状动脉造影正常的主动脉瓣返流患者心绞痛的主要机制。     

老年糖尿病患者冠状动脉血流储备的变化

目的　应用彩色多普勒超声仪检测冠状动脉血流储备 (CFR) ,观察老年糖尿病患者 CFR的变化。方法　 2 5例老年糖尿病患者为患者组 ,2 5例健康志愿者为对照组 ,比较两组的空腹血糖 (FBG)、餐后 2 h血糖 (P2 h BG)、糖化血红蛋白 (Hb A1 C)、总胆固醇 (TC)、低密度脂蛋白胆固醇 (LDL- C)及甘油三酯 (TG)、内皮素 - 1 (ET- 1 )、静息状态时患者冠状动脉的基础血流速度 (b FV)、潘生丁注射后的最大血流速度 (m FV)及 CFR。结果　糖尿病组的 FBG、P2 h BG、Hb A1 C、TG及 ET- 1水平显著高于对照组〔分别为 :9.1 2± 3.2 6 mmol/ L与 5.34± 0 .76 mmol/ L ;1 5.78± 4.98mmol/L 与 6.89± 2 .38mmol/ L;(6.3h8.5) %与 (5.2± 7.9) % ;2 .96± 0 .56与 1 .69± 0 .82 mmol/ L及 1 53.91± 1 3.50 pg/ ml与 76.2 3± 1 0 .78pg/ ml,P均<0 .0 1〕,两组的 TC及 LDL- C水平无显著差异 ,静息时的基础冠脉血流速度 (b FV)较对照组轻度上升 (P>0 .0 5) ,而潘生丁注射后 m FV及 CFR(CFR=m FV/ b FV)较对照组明显下降 (分别为 58.1± 7.9cm/ s与 73.5± 9.8cm/ s及 2 .31± 0 .49与 3.58± 0 .46,P均 <0 .0 1 )。结论　老年糖尿病患者冠状动脉血流储备明显下降。     

应用经胸冠状动脉血流显像技术评价支架术前后冠脉血流储备

目的采用经胸多普勒超声心动图冠状动脉血流显像技术观察支架术前后冠状动脉血流速度的变化,评价其对冠状动脉血流储备（CFR）的影响。方法22例冠心病患者(男18例,女4例),平均年龄（53.2±6.7）岁。对狭窄的冠状动脉行经皮冠状动脉腔内成形术（PTCA）后各置入一枚支架。分别于木前、术后72h内采用经胸多普勒冠状动脉血流显像技术记录狭窄远端静息舒张期血流峰速(r-Vd)、注射潘生丁及等长握力实验时最大舒张期血流峰速(d-Vd)及CFR。结果22例患者行支架术均获成功,狭窄率由术前(83.5±8.9)%,降至术后(5.2±9)%(P<0.05)。20支冠脉获得理想多普勒频谱（检出率90.9％）;支架术后r-Vd较术前r-Vd有增加趋势,但无统计学意义;术后静脉注射潘生丁后最大d-Vd及CFR均较术前明显增加［（0.92±0.22)m/svs(0.52±0.18)m/s,2.94±1.16vs1.88±0.40,P均<0.01］。30％患者术后CFR仍<2.0,此组与CFR≥2.0患者组比较,支架术后r-Vd明显增高［(0.45±0.19)m/svs(0.27±0.12)m/s,P<0.05］。少数患者(约18%,4／22)术前出现心绞痛,头昏等不适,静注氨茶碱或(和)含化硝酸甘油可迅速缓解。结论支架术能明显增加冠状动脉血流储备。采用经胸多普勒冠脉血流显像技术结合潘生丁、握力试验是一可行的无创性评价冠心病患者冠脉血流储备及介入治疗疗效的新方法。     

福辛普利对X综合征患者冠脉血流储备的影响

目的应用彩色多普勒超声仪检测冠状动脉血流储备(coronary flow reserve,CFR),观察福辛普利对X综合征患者CFR的影响. 方法选取26例X综合征患者,比较福辛普利(5mg或10mg)治疗前后患者血压、总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)、甘油三酯(TG)、内皮素(ET-1)、静息状态时患者冠状动脉的基础血流速度(bFV)、潘生丁注射后的最大血流速度(mFV)及冠状动脉血流储备(CFR)的变化. 结果福辛普利治疗6个月后,X综合征患者的SBP、DBP、TC、LDL-C、TG水平轻度下降(P＞0.05),ET-1水平显著下降,从(103.5±9.7)pg/ml到(77.5±12.0)Pg/ml(P＜0.05);患者的bFV改变不明显(P＞0.05),而mFV从治疗前的(57.2±8.4)cm/s上升到(72.1±7.6)cm/s(P＜0.05),CFR从治疗前的2.52±0.56上升到3.32±0.44(P＜0.01). 结论应用福辛普利治疗X综合征患者可有效改善患者的内皮功能和CFR.     

Prevalence of microvascular disease in patients with significant coronary artery disease

Coronary flow velocity reserve (CFVR) measurement using intracoronary Doppler techniques has been increasing accepted for the assessment of physiological significance of epicardial stenosis and the functional changes after coronary interventions. However, large discrepancy exists concerning the acute changes of CFVR immediately after intervention. The purpose of this study was to investigate the prevalence of microvascular dysfunction in patients with significant coronary artery disease. Intracoronary Doppler flow measurements were performed in a total of 212 patients who underwent coronary interventions because of significant epicardial stenosis using 0.014" Doppler flow wire (Cardiometrics, Inc, Mountain View, CA). Intracoronary bolus injection of adenosine (12 micrograms for the right coronary and 18 micrograms for the left coronary arteries) was used to induce hyperemic reaction. CFVR was registered as the ratio of average peak velocity during hyperemia (hAPV) to at baseline (bAPV). Successful coronary interventions either by percutaneous transluminal coronary balloon angioplasty (PTCA) or by stenting could significantly improve the CFVR. In 80 patients with PTCA, the bAPV elevated from 16.6 +/- 2.1 cm/s to 20.6 +/- 13.4 cm/s and hAPV from 30.1 +/- 15.9 cm/s to 45.2 +/- 17.7 cm/s (both p < 0.001) with PTCA and the CFVR increased from 1.94 +/- 0.78 to 2.58 +/- 0.87 correspondingly (p < 0.001). Significant elevation of coronary flow parameters were also found in 132 patients with subsequent stent implantation (bAPV from 15.3 +/- 6.7 cm/s to 18.7 +/- 9.1 cm/s, hAPV from 28.7 +/- 14.4 cm/s to 44.3 +/- 17.7 cm/s and CFVR from 1.90 +/- 0.70 to 2.59 +/- 0.87, all p < 0.001). Reduction of CFVR (< 3.0) after intervention still existed in 46 (61.3%) of 80 patients after PTCA and 88 (66.7%) of 132 patients after stenting. Moreover, CFVR < 3.0 were found in 50 (45.9%) of 109 reference vessels in patients with single vessel disease. Significant improvement of coronary flow velocity and coronary flow velocity reserve could be obtained after successful angioplasty. However, microvascualr dysfunction existed in a large proportion of patients either in normal reference vessels or in target vessels after interventions.     

Non-invasive assessment of coronary flow reserve in idiopathic dilated cardiomyopathy: hemodynamic correlations.

BACKGROUND: Impaired vasodilator myocardial blood flow response has been observed in dilated cardiomyopathy (DCMP). However, the mechanisms responsible for this blunted response are not clear. In the present study, we investigated whether the blunted vasodilator flow response is related to indices of left ventricular performance in patients with idiopathic dilated cardiomyopathy. METHODS AND RESULTS: Eighteen DCMP patients and 12 healthy subjects (C) underwent transoesophageal echocardiography within 48 h from cardiac catheterization. Coronary flow velocity reserve (CFR) was measured in the proximal LAD as the ratio of the peak diastolic coronary flow velocity (Vd-M) after intravenous administration of adenosine to peak baseline diastolic flow velocity (Vd-R). Left ventricular (LV) mass index was positively correlated with baseline coronary diastolic velocity (r=0.415; p=0.043) and inversely correlated with coronary flow reserve (r=-0.570; p=0.003). The baseline coronary diastolic velocity was higher in DCMP vs C (56+/-13 cm/s vs 35+/-12 cm/s; p=0.04). In DCMP pts Vd-R positively correlated with end-diastolic wall stress (r=0.654; p=0.01). Vd increased in both C (96+/-32 cm/s; p<0.05 vs baseline) and DCMP patients (108+/-20 cm/s; p<0.01 vs baseline). The CFR was lower in DCMP patients vs C (1.93+/-0.78 vs 2.99+/-1.01; p=0.009). In DCMP pts CFR was negatively correlated with right atrial pressure (r=-0.595; p=0.015), LVEDP (r=-0.576; p=0.015), pulmonary capillary wedge pressure (PCWP: r=-0.772; p<0.001) and positively with ejection fraction (EF: r=0.683; p=0.003). CONCLUSION: Pts with DCMP have lower CFR compared to controls. This blunted CFR is due to higher baseline coronary flow and reflects higher wall stress. The close relation between CFR and EF, PCWP and LVEDP suggests that not only a higher baseline Vd but also compressive forces due to left ventricular dysfunction might be responsible for the observed blunted adenosine-mediated coronary vasodilation.     

Role of variability in microvascular resistance on fractional flow reserve and coronary blood flow velocity reserve in intermediate coronary lesions

BACKGROUND: Fractional flow reserve (FFR) and coronary blood flow velocity reserve (CFR) represent physiological quantities used to evaluate coronary lesion severity and to make clinical decisions. A comparison between the outcomes of both diagnostic techniques has not been performed in a large cohort of patients with intermediate coronary lesions. METHODS AND RESULTS: FFR and CFR were assessed in 126 consecutive patients with 150 intermediate coronary lesions (between 40% and 70% diameter stenosis by visual assessment). Agreement between outcomes of FFR and CFR, categorized at cut-off values of 0.75 and 2.0, respectively, was observed in 109 coronary lesions (73%), whereas discordant outcomes were present in 41 lesions (27%). In 26 of these 41 lesions, FFR was <0.75 and CFR>or=2.0 (group A); in the remaining 15 lesions, FFR was >or=0.75 and CFR<2.0 (group B). Minimum microvascular resistance, defined as the ratio of mean distal pressure to average peak blood flow velocity during maximum hyperemia, showed a large variability (overall range, 0.65 to 4.64 mm Hg x cm(-1) x s(-1)) and was significantly higher in group B than in group A (2.42+/-0.77 versus 1.91+/-0.70 mm Hg x cm(-1) x s(-1); P:=0.034). CONCLUSIONS: Our findings demonstrate the prominent role of microvascular resistance in modulating the relationship between FFR and CFR and emphasize the importance of combined pressure and flow velocity measurements to evaluate coronary lesion severity and microvascular involvement.     

New signs characteristic of myocardial bridging demonstrated by intracoronary ultrasound and Doppler.

BACKGROUND: Large discrepancies exist concerning the incidence of myocardial bridging. This has been reported to be 0.5%-2.5% following coronary angiography but 15%-85% following autopsy. The purpose of the study was to use intravascular ultrasound and intracoronary Doppler to study the morphology and flow characteristics of myocardial bridging in order to find feasible parameters of this syndrome. METHODS AND RESULTS: Intravascular ultrasound was performed in 62/69 patients in whom typical angiographic 'milking effects' were present. In 48 patients, intracoronary Doppler was performed. A specific, echolucent 'half moon' phenomenon surrounding the myocardial bridge was found in all the patients. The thickness of the half moon area was 0.47 +/- 0.19 mm in diastole and 0.52 +/- 0.23 mm in systole. There was systolic compression of the myocardial bridge with a lumen reduction during systole of 36.4 +/- 8.8%. Using intracoronary Doppler, a characteristic early diastolic 'finger tip' phenomenon was observed in 42 (87%) of the patients. All patients showed no or reduced antegrade systolic flow. Coronary flow velocity reserve was 2.03 +/- 0. 54. After intracoronary nitroglycerin injection, retrograde systolic flow occurred in 37 (77%) of the 48 patients, with a velocity of -22. 2 +/- 13.2 cm. s(-1). Intravascular ultrasound revealed atherosclerotic involvement of the proximal segment in 61 (88%) of the 69 patients, with an area stenosis of 42 +/- 13%. No plaques were found in the bridge or distal segments in the 62 patients in whom it was possible to introduce the ultrasound catheter throughout the bridging segment. CONCLUSION: Myocardial bridging is characterized by the following morphological and functional signs: a specific, echolucent half moon phenomenon over the bridge segment, which exists throughout the cardiac cycle; systolic compression of the bridge segment of the coronary artery; accelerated flow velocity at early diastole (finger-tip phenomenon); no or reduced systolic antegrade flow; decreased diastolic/systolic velocity ratio; retrograde flow in the proximal segment, which is provoked and enhanced by nitroglycerin injection.     

Acute hyperglycemia does not affect the reactivity of coronary microcirculation in humans

OBJECTIVE: There is some evidence that acute hyperglycemia (H) may cause vascular dysfunction in normal subjects. This study investigates whether acute, short-term H affects coronary vasodilatory function in healthy subjects. DESIGN: Diastolic peak flow velocity in the left anterior descending coronary artery was measured at rest and after dipyridamole (0.56 mg/kg over 4 min) using transthoracic color Doppler echocardiography in 13 healthy men. Coronary flow reserve (CFR) was defined as the ratio of dipyridamole-induced coronary peak diastolic to resting peak diastolic flow velocity. CFR was measured both in euglycemia (E) and after 3 h H ( approximately 14 mmol/liter) by a variable infusion of glucose and octreotide (0.4 mg/h) to prevent increase in insulin concentration. RESULTS: Fasting plasma glucose increased to 14.3 +/- 0.33 mmol/liter during the study and maintained variability within less than 10%. Plasma insulin remained nearly stable during H. Resting diastolic flow velocity was 18.5 +/- 0.6 cm/sec in E and increased to 20.0 +/- 0.7 cm/sec during H (P < 0.005). Dipyridamole infusion produced a marked increase in coronary flow velocity, which reached values of 50.8 +/- 2.9 cm/sec in E and 51.8 +/- 2.1 cm/sec in H (P = not significant). CFR was 2.78 +/- 0.16 in E and 2.59 +/- 0.12 in H (P = not significant). CONCLUSION: Our study indicates that short-term hyperglycemia does not affect the vasodilatory response of coronary microcirculation in healthy subjects.     

Diminished coronary flow velocity reserve and aortic distensibility in elderly patients with chest pain and negative coronary angiograms

BACKGROUND AND AIMS: Aging is a dominant process that alters vascular stiffness, endothelial function and coronary flow regulation. The objective of our work was to assess simultaneously the elastic properties of the descending aorta and coronary flow velocity reserve (CFR) during the same transesophageal echocardiography (TEE) in elderly patients. METHODS: The following patients with normal epicardial coronary arteries were compared: 30 subjects under 55 years of age (group 1) and 17 patients over 55 years (group 2). A complete TEE examination was carried out in all patients, and the following aortic elastic properties were calculated from aortic diameter and blood pressure data: aortic elastic modulus [E(p)] and Young's circumferential static elastic modulus [E(s)]. Doppler evaluation of left anterior descending coronary flow velocity was performed in resting conditions and after administration of 0.56 mg/Kg dipyridamole over 4 min. Peak coronary flow velocities were measured at the 6th minute at maximum vasodilation. CFR was estimated as the ratio of hyperemic to basal peak diastolic coronary flow velocities. RESULTS: Peak hyperemic diastolic coronary flow velocities were significantly decreased (139.1+/-35.6 cm/s vs 105.7+/-39.7 cm/s, p<0.01) in patients >55 years. CFR was decreased (2.67+/-1.05 vs 2.13+/-0.56, p<0.05), whereas E(p) (in 103 mmHg, 0.59+/-0.49 vs 0.94+/-0.65, p<0.05) and E(s) (in 103 mmHg, 5.70+/-4.30 vs 8.47+/-5.14, p<0.05) were increased in patients >55 years. A correlation was found between CFR and E(p) (r=-0.20, p<0.05). CONCLUSIONS: CFR and aortic distensibility are altered in elderly patients. There is a relationship between these functional parameters.     

Alterations of phasic coronary artery flow velocity in humans during percutaneous coronary angioplasty.

BACKGROUND AND OBJECTIVES. Studies using Doppler catheters to assess blood flow velocity and vasodilator reserve in proximal coronary arteries have failed to demonstrate significant improvement immediately after coronary angioplasty. Measurement of blood flow velocity, flow reserve and phasic diastolic/systolic velocity ratio performed distal to a coronary stenosis may provide important information concerning the physiologic significance of coronary artery stenosis. This study was designed to measure these blood flow velocity variables both proximal and distal to a significant coronary artery stenosis in patients undergoing coronary angioplasty. METHODS. A low profile (0.018-in.) (0.046-cm) Doppler angioplasty guide wire capable of providing spectral flow velocity data was used to measure blood flow velocity, flow reserve and diastolic/systolic velocity ratio both proximal and distal to left anterior descending or left circumflex coronary artery stenosis. These measurements were made in 38 patients undergoing coronary angioplasty and in 12 patients without significant coronary artery disease. RESULTS. Significant improvement in mean time average peak velocity was noted in distal coronary arteries after angioplasty (before 19 +/- 12 cm/s; after 35 +/- 16 cm/s; p less than 0.01). Increases in proximal average peak velocity after angioplasty were less remarkable (before 34 +/- 18 cm/s; after 41 +/- 14 cm/s; p = 0.04). Mean flow reserve remained unchanged after angioplasty both proximal (1.5 +/- 0.5 vs. 1.6 +/- 1; p greater than 0.10) and distal (1.6 +/- 1 vs. 1.5 +/- 0.8; p greater than 0.10) to a coronary stenosis. Before angioplasty, mean diastolic/systolic velocity ratio measured distal to a significant stenosis was decreased compared with that in normal vessels (1.3 +/- 0.5 vs. 1.8 +/- 0.5; p less than 0.01). After angioplasty, distal abnormal phasic velocity patterns generally returned to normal, with a significant increase in mean diastolic/systolic velocity ratio (1.3 +/- 0.5 vs. 1.9 +/- 0.6; p less than 0.01). Phasic velocity patterns and mean diastolic/systolic velocity ratio measured proximal to a coronary stenosis were not statistically different from values in normal vessels (1.8 +/- 0.8 vs. 1.8 +/- 0.5; p greater than 0.10) and did not change significantly after angioplasty (1.8 +/- 0.8 vs. 2.13 +/- 0.9; p greater than 0.10). CONCLUSIONS. Flow velocity measurements may be performed distal to a coronary stenosis with the Doppler guide wire. Phasic velocity measurements made proximal to a coronary stenosis differed from those in the distal coronary artery. Both proximal and distal flow reserve measurements made immediately after angioplasty were of limited utility. Changes in distal flow velocity patterns and diastolic/systolic velocity ratio appeared to be more relevant than the hyperemic response in assessing the immediate physiologic outcome of coronary angioplasty.     

Coronary flow reserve in patients with vasospastic angina: correlation between coronary flow reserve and age or duration of angina

OBJECTIVES: This study sought to assess the coronary flow reserve (CFR) in patients with pure vasospastic angina (VSA). METHODS AND RESULTS: The phasic flow velocities of both spasm-positive and spasm-negative coronary arteries of the left anterior descending artery (LAD) were recorded at rest and during hyperaemia (50 microg of adenosine triphosphate infusion intracoronary) using a 0.014 inch, 15 MHz Doppler guide wire in 42 patients with pure VSA and acetylcholine (ACh)-induced coronary artery spasms (20-100 microg), and 23 controls with normal coronary arteries without ACh-induced vasospasm. These 42 patients had 16 vessels with focal spasms (>99%), 17 vessels with diffuse spasms (>90%) in the LAD, and nine vessels with ACh-induced spasms in the right coronary artery, but not the LAD. Coronary flow reserve was obtained from the ratio of the hyperaemic/baseline time-averaged peak velocity. Coronary flow reserve did not differ between patients with VSA and the controls (2.9+/-0.8 versus 3.2+/-0.7, NS). Moreover, CFR did not differ among the four cases (focal: 2.8+/-0.7; diffuse: 3.0+/-0.9; non spasm: 2.9+/-0.7 versus controls: 3.2+/-0.7, respectively, NS). Coronary flow reserve in vessels with proximal spasms was significantly higher than that in vessels with mid or distal spasms (3.4+/-0.8 versus 2.6+/-0.6, 2.6+/-0.9, p<0.05). The only significant correlation was between CFR and age (p=0.0275) or the duration of angina before admission (p=0.0405). CONCLUSIONS: There was no difference in CFR in patients with ACh-induced spasms between the spasm-positive and spasm-negative vessels. Moreover, CFR was maintained normally in vessels with diffuse spasms, as in those with focal spasms. The most important determinant factors for CFR in patients with VSA were age and the duration of angina before admission.     

Impact of intraventricular conduction delay on coronary haemodynamics: a study with intracoronary Doppler in patients with bundle branch blocks and normal coronary arteries.

AIMS: The impact of right bundle branch block (RBBB) and left bundle branch block (LBBB) on myocardial perfusion is not completely understood as data are often blurred by underlying cardiac disease. The present study investigates whether conduction delays per se affect coronary perfusion-an indirect measure of myocardial oxygen demand. METHODS AND RESULTS: Intracoronary Doppler and ultrasound were performed in 8 patients with RBBB, 10 patients with LBBB, and 10 control subjects. All patients had angiographically normal coronary arteries and normal left ventricular function. Baseline (bAPV) and adenosine-induced hyperaemic average flow velocity and coronary flow velocity reserve (CFVR) were measured in left anterior descending arteries. Intravascular ultrasound showed no difference in lumen cross-sectional area and plaque burden between groups. Patients with RBBB and LBBB had higher bAPV values than controls (19.0 +/- 4.9, 21.9 +/- 5.1, and 14.6 +/- 2.4 cm/s, respectively; ANOVA P = 0.003). There was no difference between patients with LBBB and RBBB compared with controls in CFVR (2.8 +/- 0.5, 3.0 +/- 1.0, and 3.4 +/- 0.7, respectively; ANOVA P = 0.21). CONCLUSION: Bundle branch blocks, in particular LBBB, are associated with an increased coronary flow velocity, which indicates enhanced myocardial oxygen demand on the basis of mechanoenergetic disturbance. This may contribute to the unfavourable outcome of patients with intraventricular conduction delay.