Pericardial effusion in oncological patients: current knowledge and principles of management.

BACKGROUND: This article provides an up-to-date overview of pericardial effusion in oncological practice and a guidance on its management. Furthermore, it addresses the question of when malignancy should be suspected in case of newly diagnosed pericardial effusion. MAIN BODY: Cancer-related pericardial effusion is commonly the result of localization of lung and breast cancer, melanoma, or lymphoma to the pericardium via direct invasion, lymphatic dissemination, or hematogenous spread. Several cancer therapies may also cause pericardial effusion, most often during or shortly after administration. Pericardial effusion following radiation therapy may instead develop after years. Other diseases, such as infections, and, rarely, primary tumors of the pericardium complete the spectrum of the possible etiologies of pericardial effusion in oncological patients. The diagnosis of cancer-related pericardial effusion is usually incidental, but cancer accounts for approximately one third of all cardiac tamponades. Drainage, which is mainly attained by pericardiocentesis, is needed when cancer or cancer treatment-related pericardial effusion leads to hemodynamic impairment. Placement of a pericardial catheter for 2-5 days is advised after pericardial fluid removal. In contrast, even a large pericardial effusion should be conservatively managed when the patient is stable, although the best frequency and timing of monitoring by echocardiography in this context are yet to be established. Pericardial effusion secondary to immune checkpoint inhibitors typically responds to corticosteroid therapy. Pericardiocentesis may also be considered to confirm the presence of neoplastic cells in the pericardial fluid, but the yield of cytological examination is low. In case of newly found pericardial effusion in individuals without active cancer and/or recent cancer treatment, a history of malignancy, unremitting or recurrent course, large effusion or presentation with cardiac tamponade, incomplete response to empirical therapy with nonsteroidal anti-inflammatory, and hemorrhagic fluid at pericardiocentesis suggest a neoplastic etiology.

Neuromuscular and cardiac adverse events associated with immune checkpoint inhibitors: pooled analysis of individual cases from multiple institutions and literature.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have revolutionized the management of multiple tumors, due to improved efficacy, quality of life, and safety. While most immune-related adverse events (irAEs) are mild and easily managed, in rare cases such events may be life-threatening, especially those affecting the neuromuscular and cardiac system. The management of neuromuscular/cardiac irAEs is not clear due to the lack of consistent data. Therefore, we carried out a pooled analysis of collected cases from selected Italian centers and individual data from published case reports and case series, in order to improve our understanding of these irAEs. PATIENTS AND METHODS: We collected retrospective data from patients treated in six Italian centers with ICIs (programmed cell death protein 1 or programmed death-ligand 1 and/or cytotoxic T-lymphocyte antigen 4 inhibitor) for any solid tumor who experienced neuromuscular and/or cardiovascular toxicity. Then, we carried out a search of case reports and series of neuromuscular/cardiac irAEs from ICIs with any solid tumor. RESULTS: This analysis includes cases from Italian institutions (n = 18) and the case reports identified in our systematic literature search (n = 120), for a total of 138 patients. Among these patients, 50 (36.2%) had complete resolution of their neuromuscular/cardiac irAEs, in 21 (15.2%) cases there was a clinical improvement with mild sequelae, and 53 (38.4%) patients died as a result of the irAEs. Factors significantly associated with worse outcomes were early irAE onset, within the first two cycles of ICI (Fisher P < 0.0001), clinical manifestation of both myositis and myocarditis when compared with patients who developed only myositis or myocarditis (chi-square P = 0.0045), and the development of arrhythmia (Fisher P = 0.0070). CONCLUSIONS: To the best of our knowledge, this is the largest collection of individual cases of immune-related myocarditis/myositis. Early irAE onset, concurrent development of myositis and myocarditis, as well as occurrence of arrhythmias are associated with worse outcomes and should encourage an aggressive immunomodulatory treatment.

Resistin is associated with overall survival in non-small cell lung cancer patients during nivolumab treatment.

PURPOSE: Since the role of resistin was evaluated only in patients with non-small cell lung cancer (NSCLC) not treated with immunotherapy, we aimed to evaluate levels of resistin during immunotherapy (nivolumab) and its prognostic role with regard to OS. METHODS/PATIENTS: From a cohort of 78 patients with advanced NSCLC enrolled in a prospective study at Ospedale Policlinico San Martino in Genoa (Italy), 43 patients have been considered for this sub-analysis because of the availability of samples. Before and during nivolumab administration, clinical information and blood samples were collected and resistin, matrix metalloproteinase (MMP)-8, MMP-9, and myeloperoxidase were evaluated by enzyme-linked immunosorbent assay (ELISA). RESULTS: Median age was 71 with a prevalence of males and former smokers. Median resistin levels presented a peak at cycle 2 and then dropped down until the last cycle. Resistin correlated with all neutrophil degranulation products at cycle 1 (except for MMP-9) and at cycle 2 as well as with white blood cells and neutrophils. By a ROC curve analysis, a resistin value at cycle 2 of 19 ng/mL was tested as the best cut-off point for OS. Kaplan-Meier analysis demonstrated that patients above the resistin cut-off experienced a reduced OS (median OS 242.5 vs. 470 days, p = 0.0073), as confirmed by Cox proportional hazards regression analysis. CONCLUSIONS: Resistin levels > 19 ng/mL at the time of the second cycle of nivolumab treatment independently predict a reduced OS in patients with advanced NSCLC.

Relationship between vitamin D status and left ventricular geometry in a healthy population: results from the Baltimore Longitudinal Study of Aging.

OBJECTIVES: The effects of vitamin D on the heart have been studied in patients with cardiac disease, but not in healthy persons. We investigated the relation between vitamin D status and left ventricular (LV) structure and function in community-dwelling subjects without heart disease. DESIGN: The relationship between concentrations of 25-hydroxyvitamin D [25(OH)D], a marker of vitamin D reserve, and LV transthoracic echocardiography measures was analysed in 711 participants in the Baltimore Longitudinal Study of Aging who were without cardiac disease. RESULTS: Mean 25(OH)D in the study population was 32.3 ± 11.4 ng mL(-1) ; only 15.5% of subjects had moderate or severe vitamin D deficiency [25(OH)D < 20 ng mL(-1) ]. Adjusting for age, body mass index, cardiovascular disease risk factors, physical activity, calcium and parathyroid hormone, 25(OH)D was positively correlated with LV thickness (ß 0.095, SE 0.039, P < 0.05) and LV mass index (ß 7.5, SE 2.6, P < 0.01). A significant nonlinear relation between 25(OH)D and LV concentric remodelling was observed. LV remodelling was more likely in participants with 25(OH)D levels <30 ng mL(-1) [odds ratio (OR) 1.24; 95% confidence interval (CI) 0.83-1.85] or ≥38 ng mL(-1) (OR 1.73; 95% CI 1.13-2.65), compared with those with 30-37 ng mL(-1) 25(OH)D. Consistently, LV relative wall thickness was significantly lower (P for trend=0.05), and LV diastolic internal diameter index (P for trend<0.05) and end-diastolic volume index (P for trend<0.05) were significantly higher in subjects with 30-37 ng mL(-1) 25(OH)D compared to the rest of the study population. There was a significant interaction between 25(OH)D and hypertension on the risk of LV hypertrophy (P < 0.05). CONCLUSIONS: In a population-based sample of predominantly vitamin D-sufficient subjects without heart disease, LV geometry was most favourable at intermediate 25(OH)D concentrations.

Reduction of cardiovascular morbidity and mortality in type 2 diabetes. A rational approach to hypoglycemic therapy.

Type 2 diabetes mellitus is the single most important risk factor for the development of coronary artery disease. Unfortunately, the traditional therapeutic strategies for the treatment of hyperglycemia have proven to be ineffective in preventing cardiovascular complications. In recent years the number of available hypoglycemic agents has increased and considerable progress has been made regarding the comprehension of the pathophysiology of diabetes and its vascular complications. In the present article we firstly present benefits and risks of intensive vs standard hypoglycemic intervention, and the pros and cons of therapy targeted to postprandial hyperglycemia. Secondly, we discuss the cardiovascular effects of sulfonylurea agents and insulin, focusing on the role of intensive insulin treatment in the context of acute coronary syndromes. Thirdly, we review the epidemiological, clinical and experimental evidence linking insulin resistance and cardiovascular disease. Finally, we present the rationale and the role of metformin and thiazolidinedionetherapy in the prevention of cardiovascular complications. We conclude that the optimal use of the full spectrum of hypoglycemic agents has the potential to play a key role in the prevention of diabetes-related macrovascular complications.

Metalloproteinases 2 and 9 are increased in plasma of patients with heart failure.

BACKGROUND: Progression of heart failure is associated with interstitial changes in the heart and in areas distant from the heart. Enhanced expression of metalloproteinases 2 and 9 and of metalloproteinases tissue inhibitors 1 and 2 have been found in ventricular tissue of patients with heart failure. Our aim was to determine whether increased activity of metalloproteinase-2, metalloproteinase-9 and of metalloproteinases tissue inhibitor-1 and metalloproteinases tissue inhibitor-2 were also present in plasma of patients with heart failure. DESIGN: Levels of metalloproteinase-2, metalloproteinase-9 and of metalloproteinase tissue inhibitor-1 and metalloproteinases tissue inhibitor-2 were measured in venous blood of 51 patients with heart failure, and were compared with levels of 52 control subjects. Samples collected from patients and control subjects were assayed for gelatinolytic activity (zymography) and for protein levels. RESULTS: Compared with the control subjects, the patients with heart failure had a significant increase in activity levels (mean +/- SE, ng mL(-1)) of prometalloproteinase-9 (95.1+/-11.2 and 38.9+/-4.5*), activ. metalloproteinase-9 (18.4+/-2.5 and 10.9+/-1.3*), and of prometalloproteinase-2 (571.4+/-26.1 and 456.8+/-21.1*) (respectively: patients and control subjects; *P<0.05). Metalloproteinases tissue inhibitor-1, but not metalloproteinases tissue inhibitor-2 protein values were higher in the patients. Among the patients, clinical status and New York Heart Association (NYHA) class did not correlate with the metalloproteinase concentrations. Positive correlations with left ventricular volumes, and negative correlations with lipid values were obtained for prometalloproteinase-2; positive correlations with total number of white cells and neutrophils were obtained for prometalloproteinase-9; and positive correlations with lactate dehydrogenase, serum fibrinogen, aspartate transaminases were found for activ. metalloproteinase-9. CONCLUSIONS: Regardless of the clinical phase of heart failure, elevated levels of activity and of circulating metalloproteinase protein levels suggest the presence of persistent extracellular remodeling in patients with heart failure.

High doses of atorvastatin do not affect activity of prothrombinase in patients with acute coronary syndromes.

Membrane-dependent coagulation processes play a key role in acute coronary syndromes (ACS), where the generation of thrombin depends on the complex of activated factors X and V (prothrombinase complex) assembled on activated platelets. The aim of the present study was to evaluate prothrombinase activity in patients with ACS and to examine the effect of treatment with 80 mg/day atorvastatin on prothrombinase activity. Blood samples were obtained at admission from 22 patients with ACS, and then again at 2 weeks and at 16 weeks after double-blind randomization to either placebo or atorvastatin. Prothrombinase activity was evaluated by measuring the generation of thrombin by in vitro reconstructed thrombi, and also by measuring plasma levels of prothrombin fragment F1 + 2. Twenty age-matched subjects with stable angina and 11 without coronary disease were used as controls. At admission, prothrombinase activity and F1 + 2 were significantly higher in ACS patients than in controls. Prothrombinase activity was still high at 2 weeks while it returned to normal levels at 16 weeks. F1 + 2 remained high both at 2 and at 16 weeks. Our data indicate that prothrombinase activity is high in patients with ACS, and that it is not affected by high-dose atorvastatin.

Maximal endothelial tissue plasminogen activator release is not impaired in patients with acute coronary syndromes before heparin treatment.

Procoagulant and fibrinolytic disturbances are described in patients with acute coronary syndromes (ACS), but whether defective maximal tissue plasminogen activator (t-PA) release from the endothelium is also present is still controversial. Previous studies did not take into consideration the contribution of heparin, which strongly affects fibrinolysis. Accordingly, in this study, we measured maximal t-PA release in patients with ACS before, during, and after heparin treatment. Maximal t-PA release was measured by the venous occlusion test in 38 hospitalized patients with confirmed ACS (18 acute myocardial infarctions and 20 unstable anginas) before starting heparin, during heparin treatment, and 4 and 12 h after discontinuation. Plasma plasminogen activator inhibitor type 1 (PAI-1), D-dimer and prothrombin fragment F1 + 2 were also measured. Eighteen age-matched subjects with no evidence of coronary disease were used as controls. At admission, patients showed significantly higher plasma levels of t-PA, PAI-1, and F1 + 2 than controls. Before heparin, maximal t-PA release was similar in patients and controls. Heparin treatment was associated with a significant increase of plasma t-PA, while it did not affect maximal t-PA release. Coagulative and fibrinolytic disturbances are present in patients with ACS, but these do not include maximal t-PA release. Among our patients, maximal t-PA release appears stable over time and is not affected by heparin treatment.

N-acetyl-cysteine reduces neointimal thickening and procoagulant activity after balloon-induced injury in abdominal aortae of New Zealand white rabbits.

BACKGROUND: Procoagulant activity and oxidative stress generated by balloon injury to normal vessels promote the migration of medial smooth muscle cells and their proliferation in the intima. We hypothesised that administering levo N-acetyl-cysteine (NAC) i.v. at the time of injury, and s.c. before and after injury would reduce neointimal formation 4 weeks later and would regulate procoagulant activity in vessels with neointima undergoing ballooning a second time. METHODS AND RESULTS: at the time of injury rabbits received: NAC, unfractionated heparin (HEP) or both (NAC + HEP). Neointimal thickening at 28 days, calculated as the ratio between the intimal and medial area, was attenuated after NAC, HEP and NAC+HEP by 39%, 30% and 47% respectively when compared to untreated injured animals (CONTROLS) (p <0.05). At 28 days, bound thrombin activity and platelet adhesion 1 h after a repeated balloon injury decreased in animals receiving NAC, HEP and NAC+HEP bv 54%, 63% and 64% for thrombin activity (p <0.05 vs CONTROLS), and by 56%, 66% and 75% respectively for 111Indium-platelet deposition (p <0.05 vs CONTROLS). CONCLUSIONS: NAC in-vivo was effective in reducing neointimal thickening and procoagulant response after balloon injury.

Sulfonylurea treatment of type 2 diabetic patients does not reduce the vasodilator response to ischemia.

OBJECTIVE: Sulfonylureas block the activation of vascular potassium-dependent ATP channels and impair the vasodilating response to ischcmia in nondiabetic individuals, but it is not know whether this occurs in type 2 diabetic patients under chronic treatment with these drugs. Glimepiride, a new sulfonylurea, apparently has no cardiovascular interactions. The aim of our study was to compare the effect of the widely used compound glibenclamide, the pancreas-specific glimepiride, and diet treatment alone on brachial artery response to acute forearm ischemia. RESEARCH DESIGN AND METHODS: Brachial artery examination was performed by a high-resolution ultrasound technique on 20 type 2 diabetic patients aged mean +/- SD) 67 +/- 2 years and on 18 nondiabetic patients matched for age, hypertension, and dislipidemia. Diabetic subjects underwent three separate evaluations at the end of each 8-week treatment period, during which they received glibenclamide, glimepiride, or diet alone according to crossover design. Scans were obtained before and after 4.5 min of forearm ischemia. Postischemic vasodilation and hyperemia were expressed as percent variations in vessel diameter and blood flow. RESULTS: Postischemic vasodilation and hyperemia were, respectively, 5.42 +/- 0.90 and 331 +/- 38% during glibenclamide, 5.46 +/- 0.69 and 326 +/- 28% during glimepiride, and 5.17 +/- 0.64 and 357 +/- 35% during diet treatment (NS). These results were similar to those found in the nondiabetic patients (6.44 +/- 0.68 and 406 +/- 42%, NS). CONCLUSIONS: In type 2 diabetic patients, the vasodilating response to forearm ischemia was the same whether patients were treated with diet treatment alone or with glibenclamide or glimepiride at blood glucose-lowering equipotent closes.

Detection of acute myocardial infarction by 99mTc-labeled D-glucaric acid imaging in patients with acute chest pain.

UNLABELLED: Definitive diagnosis of acute myocardial infarction early in the process is often difficult. An imaging agent that localized quickly and specifically in areas of acute necrosis could provide this critical diagnostic information. To determine whether imaging with 99mTc-labeled D-glucaric acid (GLA) could provide this information, we imaged a group of patients presenting with symptoms suggestive of acute infarction. METHODS: Twenty-eight patients presenting to the emergency department with symptoms highly suggestive of acute infarction were injected with 99mTC-GLA and imaged about 3 h later. RESULTS: The sensitivity of lesion detection was remarkably time dependent. Fourteen patients with acute infarction injected within 9 h of onset of chest pain had positive scans, even in the presence of persistent occlusion. The remaining 14 patients had negative scans. Nine patients with negative scans had acute infarction but were injected more than 9 h after onset of chest pain. The final diagnosis in the remaining 5 patients was unstable angina (3 injected <9 h and 2 injected >9 h after onset of chest pain). Six patients were reinjected with 99mTc-GLA 4-6 wk after their initial study to determine whether persistent positive scans occurred with this agent. All 6 had negative scans. CONCLUSION: This study suggests that 99mTc-GLA localizes in zones of acute myocardial necrosis when injected within 9 h of onset of infarction.

Evaluation of growth hormone administration in patients with chronic heart failure secondary to coronary artery disease.

We have examined the effects of 6 months of treatment with growth hormone (GH) (0.02 U/kg/day) in 10 patients with chronic postischemic cardiac failure. Ten patients matched for age, body mass index, functional class, and ejection fraction served as a control group. In the GH group, 1 patient died and 2 were withdrawn from the study because of arrhythmia or worsening of heart failure. In the control group, 1 patient died and 1 patient was withdrawn from the study because of progressive heart failure. Among GH patients, those with an unfavorable outcome had a greater left ventricular end-diastolic diameter (79, 82, and 88 mm) on entry to the study than patients without adverse events (range 62 to 72 mm). At the end of the study, the seven GH patients reported a feeling of well-being and had a significant increase in their exercise test duration (462 +/- 121 vs 591 +/- 105 seconds, p <0.05). Low baseline insulin-like growth factor-I values were increased with GH treatment (189 +/- 52 vs 100 +/- 22 ng/ml, p <0.01). GH did not change left ventricular diameters or wall thickness. A trend toward decreased serum triglyceride levels and adipose body tissue associated with an increase in high-density lipoproteins was observed in the GH group. In conclusion, our present data support previous suggestions that GH treatment exerts some beneficial effects in patients with chronic, stabilized, moderately severe heart failure, but may have deleterious effects in patients with more severe heart failure.

[Treatment aspects of unstable angina. Costs and payments for DRG]. / Aspetti gestionali dell'angina instabile. Costi reali e tariffe per DRG.

Patients with unstable angina fall into a wide prognostic and therapeutic spectrum but, in general, have great access to specialty care and invasive procedures. In the modern era, in which admissions for unstable angina outnumber those for myocardial infarction, and growing economic pressures are placed on health care systems, cardiologists must re-examine clinical strategies for treating unstable angina in the light of health-cost accounting. The aims of the present study were to examine the current management of patients admitted to our cardiology department and to calculate the medical costs. A patient schedule was drawn up to prospectively register the number and type of cardiac processes carried out during hospitalization for all unstable angina patients in the period between March 1st and May 30th, 1995. Time (minutes) actually spent by both physicians and nurses for each cardiac process were carefully recorded in order to calculate the activity budget. The effective economic budget was built for each cardiac process taking into account salaries, consumable supplies, equipment service contracts, depreciation and indirect medical and non medical costs for CCU and ward. Based to the Diagnosis Related Groups (DRG) system, 53 out of 318 patients (16%) were admitted with documented or suspected unstable angina and allocated to discharge into four DRGs: DRG 140-medically treated unstable angina: 18 patients; DRG 124-unstable angina with angiography: 16 patients; DRG 122-unstable angina evolving in myocardial infarction: 6 patients; DRG 112-unstable angina with angioplasty: 13 patients. The mean cost for hospitalized patient with unstable angina was 5,574,958 Italian Liras (DRG 140 = 2,687,719; DRG 124 = 2,800,347; DRG 122 = 6,086,563; DRG 112 = 12,751,454). The difference in costs was essentially related to the procedures involved in medical care, DRGs with expensive cardiac processes having higher costs. Furthermore, these data show a deep discrepancy between "real" costs and current DRG reimbursement. In conclusion, data show the standard management of unstable angina at our center; calculating the true costs of unstable angina is the first step towards maximizing resources and optimizing benefits.

[Cost analysis for DRG and PRG in the treatment of acute myocardial infarction in hospitalized patients]. / Analisi dei costi per DRG e PRG del trattamento dell'infarto miocardico acuto in regime di ricovero ospedaliero.

The cost of diagnostic and therapeutic procedures in patients with acute myocardial infarction (AMI) during hospitalization was determined using both the Diagnosis Related Group (DRG) and Process Related Group (PRG) systems. This cost-analysis system was planned and performed to estimate the cost of medical and non-medical staff involved in patient care, as well as commensurate costs. Over a three-month period, 45 patients discharged with a diagnosis of AMI, equivalent to 410 code ICD-9-CM, were enrolled in the study. The collected data were then processed and the cost for each DRG was derived. The mean cost borne for each patient with AMI was 5,864,345 Italian lire with a maximum of 17,138,300 lire for DRG 112 and a minimum of 3,332,329 lire for DRG 123. Our data suggest that in patients with AMI, there is profound discrepancy between the current DRG reimbursements and "real" cost, for example in DRG 112 (a discrepancy equivalent to 166%). The cost difference is essentially related to different procedures involved in medical care and, therefore, it follows that the overall cost of patient with AMI is primarily related to PRG cost and is largely independent of other components. These results prove that therapeutic strategies are very important in determining the cost for each DRG and that the cost for each DRG can change in relation to the PRG performed and to the progression of illness. The utilization of DRG and PRG systems appears to be an essential tool that can be used to build a system in which not only efficiency but also quality of care are evaluated.

Recognition and treatment of unstable angina.

Despite the growing number of patients discharged from hospital with a diagnosis of unstable angina, the diagnostic procedures and treatment of unstable angina are still greatly debated, as they have been for patients with myocardial infarction. In recent years the definition and classification of the clinical syndrome of unstable angina has been subjected to numerous proposals by distinguished cardiologists. An attempt to clarify and redefine practical guidelines for different subgroups of patients has been developed and carried out by the US Agency for Health Care Policy and Research (AHCPR). The current medical approach to treatment of patients with unstable angina is discussed in detail, analysing the role of antiplatelet medications, beta-blockers, nitrates, heparin and calcium antagonists. The small subgroup of patients with refractory unstable angina should undergo urgent coronary angiography and revascularisation. Previous and current research on medical treatment with thrombolytic therapy, GPIIb/IIIa platelet receptor blockers and direct thrombin inhibitors is outlined, keeping in mind one of the main aspects of pathophysiology of the disease, that is ongoing thrombus formation. In the future, a more aggressive strategy aimed at normalising the atherogenic lipid profile in this very high risk group of patients should be carried out, based on the positive results of lipid-lowering drug trials both in primary and secondary prevention.

Cerebral blood flow reserve in patients with syndrome X.

BACKGROUND: Patients with syndrome X frequently show disorders of oesophageal motility, bronchial reactivity or impaired vasodilator capacity of peripheral vascular beds. For these reasons, it has been suggested that syndrome X may represent a generalized abnormality of vascular and non-vascular smooth muscle function, rather than an isolated coronary problem. OBJECTIVE: To measure the cerebral blood flow and cerebrovascular vasodilator reserve in syndrome X patients and in controls. METHODS: We measured the cerebral blood flow and cerebrovascular reserve in 16 patients with syndrome X [11 women, aged 59.5 +/- 10.8 years (mean +/- SD)] and in 16 age-matched healthy volunteers. No patients had evidence of stenoses of carotid and vertebral arteries on Doppler sonography. Cerebral blood flow was measured by the 133Xe inhalation method, using the initial slope index as the cerebral blood flow index. After a baseline measurement, a second cerebral blood flow measurement was performed 20 min after administration of 10 mg/kg acetazolamide intravenously. Acetazolamide is known to be a potent cerebral vasodilator. The percentage increase in cerebral blood flow after acetazolamide administration was considered an index of cerebrovascular vasodilator reserve. RESULTS: Under basal conditions, both regional and global cerebral blood flow were nearly identical in the control group and in the patient group (initial slope index 50.2 +/- 3.8 versus 50.3 +/-6.2, NS). After acetazolamide administration, the cerebral blood flow increase was 29.0 +/- 14% in the patient group and 29.5 +/- 11% in the control group (NS). CONCLUSIONS: Our data show that cerebral blood flow and cerebrovascular vasodilator reserve were preserved in a series of patients with syndrome X. These results are not consistent with the hypothesis of a diffuse smooth muscle disorder.