Roberto Lorenzoni

Coronary vasodilation is impaired in both hypertrophied and nonhypertrophied myocardium of patients with hypertrophic cardiomyopathy: A study with nitrogen-13 ammonia and positron emission tomography

To assess regional coronary reserve in hypertrophic cardiomyopathy, regional myocardial blood flow was measured in 23 patients with hypertrophic cardiomyopathy and 12 control subjects by means of nitrogen-13 ammonia and dynamic positron emission tomography. In patients with hypertrophic cardiomyopathy at baseline study, regional myocardial blood flow was 1.14 +/- 0.43 ml/min per g in the hypertrophied (20 +/- 3 mm) interventricular septum and 0.90 +/- 0.35 ml/min per g (p less than 0.05 versus septal flow) in the nonhypertrophied (10 +/- 2 mm) left ventricular free wall. These were not statistically different from the corresponding values in control subjects (1.04 +/- 0.25 and 0.91 +/- 0.21 ml/min per g, respectively, p = NS). After pharmacologically induced coronary vasodilation (dipyridamole, 0.56 mg/kg intravenously over 4 min), regional myocardial blood flow in patients with hypertrophic cardiomyopathy increased significantly less than in control subjects both in the septum (1.63 +/- 0.58 versus 2.99 +/- 1.06 ml/min per g, p less than 0.001) and in the free wall (1.47 +/- 0.58 versus 2.44 +/- 0.82 ml/min per g, p less than 0.001). In addition, patients with hypertrophic cardiomyopathy who had a history of chest pain had more pronounced impairment of coronary vasodilator reserve than did those without a history of chest pain. After dipyridamole, coronary resistance in the septum decreased by 38% in patients without a history of chest pain, but decreased by only 14% in those with such a history (p less than 0.05). Coronary resistance in the free wall decreased by 45% in patients without and by 27% in those with a history of chest pain (p = 0.06).(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary hemodynamics and myocardial metabolism in patients with syndrome X: Response to pacing stress

Coronary hemodynamics, myocardial metabolism and left ventricular function at rest and after incremental atrial pacing were evaluated in 12 patients with stress-induced angina and ST segment depression, angiographically normal coronary arteries and no evidence of spasm, generally labeled as syndrome X, and in 10 normal subjects. At baseline study, great cardiac vein flow was comparable in patients and control subjects. During pacing, an equivalent rate-pressure product was reached in the two groups, but the slope of the relation between rate-pressure product and great cardiac vein flow was significantly less steep in patients than in normal subjects (0.0027 vs. 0.0054 ml/mm Hg.beat, p less than 0.001). Nevertheless, the left ventricular ejection fraction was comparable in both groups at rest (66 +/- 6% vs. 71 +/- 7%, p = NS) and during pacing (71 +/- 7% vs. 66 +/- 5%, p = NS). At baseline study, myocardial glucose extraction was more efficient in patients with syndrome X (p less than 0.05), but net myocardial exchange of pyruvate and alanine was, respectively, smaller and greater than in control subjects. Lactate was extracted to a similar extent in the two groups and in no instance was net lactate release observed during pacing or recovery. During pacing and recovery, patients with syndrome X showed net pyruvate release, unlike the control subjects in whom net pyruvate exchange was positive. In addition, patients with syndrome X continued to show net myocardial extraction of alanine during spacing and recovery, whereas normal subjects produced alanine throughout the study. Myocardial carbohydrate oxidation increased significantly during maximal pacing in normal subjects but not in patients, in whom it always remained below (p less than 0.01) the concurrent rate of myocardial uptake of carbohydrate equivalents (glucose, lactate, pyruvate, alanine). Myocardial energy expenditure was significantly lower in patients than in control subjects at maximal rate-pressure product levels (p less than 0.01). The metabolic pattern in patients with syndrome X therefore is not consistent with classic ischemia, although differences in the net exchange of circulating substrates (glucose, pyruvate, alanine) can be demonstrated. Thus, in patients with syndrome X, the symptoms, electrocardiographic signs and impairment in the increase in great cardiac vein flow during pacing coexist with preserved global and regional left ventricular function and myocardial energy efficiency.

Coronary reserve and exercise ECG in patients with chest pain and normal coronary angiograms.

BackgroundCoronary vasodilator reserve is reduced in some patients with a history of chest pain and angiographically normal coronary arteries. ECG changes suggestive of myocardial ischemia during exercise also can be demonstrated in a subset of these patients. Methods and ResultsWe have investigated the correlation between coronary vasodilator reserve, assessed with 13N-labeled ammonia and positron emission tomography, and the ECG during exercise stress in 45 patients with a history of chest pain, angiographically normal coronary arteries, and a negative ergonovine test. ST segment depression on the ECG during exercise was present in 29 of 45 patients. Mean resting left ventricular blood flow was 1.04±0.22 ml · min−1 · g−1; it increased to 1.32±0.47 ml · min−1 g−1 (p<0.01 versus baseline value) during atrial pacing and to 2.52±0.96 ml · min−1 · g−1 (p<0.01 versus baseline value) after dipyridamole (0.56 mg/kg i.v.). No regional flow defects could be demonstrated in any patient during pacing or after dipyridamole. Myocardial flows after dipyridamole, however, did not show a normal frequency distribution (Kolmogorov-Smirnov test), and two patient populations could be identified. Twenty-nine (67%) patients had a mean left ventricular flow of 3.02±0.33 ml · min−1 · g−1 after dipyridamole (range, 2.13–5.46 ml · min−1 · g−1), and 14 (33%) patients had a mean flow of 1.48±0.29 ml · min−1 · g−1 (range, 1.06–2.04 ml · min−1 · g−1, p<0.01 versus the “high-flow group”). ConclusionsApproximately one third of patients in our series showed a reduced coronary vasodilator reserve. Although 12 of 14 patients in the “low-flow group” had ST segment depression during exercise stress, 16 of 29 patients in the high-flow group also had ST segment depression during exercise stress. Therefore, despite a good sensitivity (86%) in identifying patients with a blunted increment of coronary flow, the ECG response during exercise stress appears to have a rather low specificity (45%). This suggests that factors other than reduced coronary reserve and myocardial ischemia may play a role in the genesis of the ST segment depression in these patients.

Coronary vasodilator reserve is impaired in patients with hypertrophic cardiomyopathy and left ventricular dysfunction.

BACKGROUND We tested the hypothesis that a reduced delivery of blood to the myocardium is involved in the development of systolic dysfunction of patients with hypertrophic cardiomyopathy (HCM). METHODS AND RESULTS Eighty-four patients with HCM (62 men, age 43 +/- 12 years) were studied. Left ventricular dimensions and function (fractional shortening) were evaluated by 2-dimensional echocardiography. Myocardial blood flow (MBF) was measured by N13 -ammonia or O15 -water and positron emission tomography at baseline and after dipyridamole; coronary vasodilator reserve (CVR) was calculated as dipyridamole/baseline MBF. Patients with HCM in advanced New York Heart Association (NYHA) classes had lower dipyridamole MBF (NYHA class I = 1.57 +/- 0.64 vs class II = 1.52 +/- 0.58 vs class III = 0.96 +/- 0.32 mL/min per gram; analysis of variance, P <.05) and CVR (NYHA class I = 1.93 +/- 0.64 vs class II = 1.69 +/- 0.54 vs class III = 1.40 +/- 0.43; analysis of variance, P <.05). A positive linear correlation between fractional shortening and dipyridamole MBF was demonstrated (R = 0.23, P <.05), and patients with abnormal fractional shortening had lower dipyridamole MBF (1.07 +/- 0.43 vs 1.58 +/- 0.62 mL/min per gram, P <.01). CONCLUSIONS Systolic dysfunction in HCM may be caused by a more severe alteration of the coronary vasodilator capacity.

Tailored use of transradial access for above-the-knee angioplasty.

Purpose To report the results and complications of a single-center experience of above-the-knee angioplasty via transradial access (TRA). Methods In a prospective study, 110 consecutive patients (88 men; mean age 72 years, range 37–90) referred for critical limb ischemia (26, 24%) or claudication were eligible for lower limb angioplasty via TRA (patients with TASC D lesions of the superficial femoral artery and below-the-knee lesions were excluded). Results The majority of patients (84, 76%) were treated via a left TRA. A total of 170 lesions were addressed, of which 38 (22%) were occlusions; 113 stents were positioned in 82 patients. The overall technical success rate was 91%, with a 63% success rate in occlusions and a 98% success rate in stenoses; by location, the success rates were 91% in suprainguinal lesions and 90% in infrainguinal lesions. No hemorrhagic or local complications requiring surgery were observed. At 1-month follow-up, 101 patients had a downward shift of at least one category in the Rutherford classification of symptoms (clinical success rate 92%); 18 (16%) patients had occlusion of their access radial artery, but none had symptoms or discomfort. Conclusion The present study demonstrates that TRA is a safe and effective approach for lower extremity arterial revascularization, at least for interventionists with longstanding experience in TRA and in selected anatomical subsets.

Radial artery access for above the knee angioplasty: a feasibility study

AIMS Lower limb angioplasty is usually performed by transfemoral access despite the risk of local complications. Transradial access (TRA) has gained acceptance for coronary interventions. The aim of this study was to evaluate the feasibility and safety of TRA for above the knee (ATK) angioplasty. METHODS AND RESULTS Twenty-five consecutive patients (eight females; mean age 72, range 55-85 years; seven symptomatic for critical limb ischaemia, 18 for claudication) underwent ATK angioplasty by left (19) or right (6) TRA. A total of 32 lesions were addressed; 16 stents were positioned in 12 patients with an overall success rate of 81%, and a success rate of 38% on occlusions and of 96% on stenoses. The overall success rate on the 16 supra-inguinal lesions was 81%, (success rate 60% on occlusions and 91% on stenoses). The overall success rate on the 16 infra-inguinal lesions was 81%, (success rate 0% on occlusions and 100% on stenoses). Any haemorrhagic complications or local complications needing surgery were observed in the cohort of patients. CONCLUSIONS TRA can represent a feasible and safe alternative for ATK angioplasty in case of difficult femoral access.

Tools & Techniques: Above the knee angioplasty by transradial access

Background Analysing the distribution of peripheral arterial disease in non-diabetic patients, about one third of the lesions affect the aortoiliac segment and more than half are localised in the superficial femoral artery (SFA). As TASC A and TASC B lesions are commonly treated with an endovascular approach and TASC C lesions are increasingly treated percutaneously 1 , above the knee (ATK) arterial

A computer protocol to evaluate subjects with chest pain in the emergency department: a multicenter study.

Objective Chest pain is a frequent cause of medical admission to the emergency department and the main differential diagnosis is between coronary and non-coronary chest pain. We elaborated a computer protocol for the management of patients with chest pain. Methods The computer protocol was made of three sections according to clinical, electrocardiographic and biochemical data. Each section was coded by a letter indicating the probability of coronary chest pain for each section. The combination of the three letters formed a score string used to assign patients to four subgroups of overall probability of coronary chest pain (low, medium-low, medium-high, and high). Low-probability patients were discharged from the emergency department, whereas high-probability patients were admitted to the coronary care unit. The medium-probability patients underwent further evaluation by means of a stress test and were re-classified as having a final low probability (negative test) or high probability (positive test). Results We evaluated 472 patients (mean age 64 years, range 18–97 years; 47% female). The incidence of coronary events in patients with low, medium-low, medium-high and high overall probability was 1.9, 12.8, 13.5 and 68.0%, respectively (P < 0.05). The positive and negative predictive values of the protocol were 64.7 and 97.1%, respectively. Conclusions Our computer protocol represents a reliable method for the management of patients with chest pain and a non-diagnostic electrocardiogram.

Cardiovascular Risk Management: An Overview

Cardiovascular disease (CVD) is a leading cause of mortality and is responsible for one-third of all global deaths annually. This translates into the deaths of 17 million people each year [1, 2]. Despite research-based gains in the treatment of CVDs, they remain the leading killer in the USA and in most developed areas of the world. Coronary heart disease (CHD) accounts for the majority of CVD deaths, disproportionately afflicts racial and ethnic minorities, and is a prime target for prevention. Hypertension is the most prevalent CVD, affecting at least 600 million people, and is an important contributor to cardiovascular mortality and morbidity [3]. Nearly 85% of the global mortality and disease burden from CVD is borne by low- and middle-income countries.

Endovascular treatment of iliac and common femoral arteries disease by the transradial access: A prospective, feasibility study

AIM To report feasibility and safety of endovascular interventions on iliac and common femoral arteries, using the transradial access (TRA). METHODS 100 consecutive patients (19 women; mean age 71, range 37-90years) with critical limb ischemia (30%) or claudication, and TASC A-D lesions in iliac or common femoral arteries, were prospectively enrolled, from January 2013 to June 2015, to be treated via the TRA. Exclusion criteria included no palpable radial arteries (RA) and the presence of a fistula for hemodialysis. Patients were evaluated for procedural technical success, in-hospital complications, and 30days clinical success (defined as improvement of at least one grade in the Rutherford classification of symptoms). RESULTS A total of 131 iliac and common femoral arteries lesions were treated (58 in common iliac arteries, 38 in external iliac arteries and 35 in common femoral arteries). Ninety-two stents were deployed in 58 patients. Procedural technical success was achieved in 91% of the lesions; with 95% technical success rate in common iliac arteries, 87% in external iliac arteries and 89% in common femoral arteries; with 72% technical success rate in occlusions and 98% in stenosis. No in-hospital complications were observed. At 30days, 93 patients (93%) had an improvement of at least one category in the Rutherford classification of symptoms (clinical success rate 93%); 12 patients (12%) had an asymptomatic occlusion of the RA. CONCLUSIONS TRA can be used to treat iliac and common femoral arteries lesions with a high grade of technical success and a low rate of complications.