Creatine supplementation improves muscle strength in patients with congestive heart failure

BACKGROUND

Both, cardiac and skeletal muscle creatine levels are depressed in patients with congestive heart failure (CHF). Oral supplementation of creatine (Cr) could increase physical performance in healthy volunteers. We therefore hypothesized that oral creatine supplementation improves skeletal muscle strength, quality of live and symptom-limited performance in patients with CHF.

METHODS

In a double-blind, placebo-controlled and crossover-designed study, 20 patients suffering from congestive heart failure more than 6 months and a peak oxygen uptake (peak VO2) below 20 ml/min/kg received 4 x 5 g Cr daily vs. placebo for 6 weeks and were crossed over for the following 6 weeks. Peak VO2, VO2 at the anaerobic threshold (VO2AT), ejection fraction (EF), distance in 6-minute-walk-test (6 min W), and muscle strength (Modified Sphygmomanometer (MS)) were determined at baseline, after 6, and after 12 weeks. Dyspnoea after 6-minute-walk-test was measured using the Borg Scale. Quality of live was assessed with the Minnesota Living with Heart Failure Questionnaire (MLHFQ).

RESULTS

13 of 20 Patients finished the study. After 6 weeks of creatine supplementation there was a significant increase in body weight and muscle strength compared to baseline and placebo (p < 0.05). However, there was no significant change in peak VO2, VO2AT, walking distance, quality of life assessment and EF.

CONCLUSION

Short-term creatine supplementation inaddition to standard medication in patients with CHF leads to an increase in body weight and an improvement of muscle strength. This effect is restricted to the time of supplementation.

[Implantation of a re-synchronization device in a patient with persistent left superior vena cava-a case report]

We report an implantation of a cardiac re-synchronization system in a patient with persistent left superior vena cava. This anomaly occurs in 0.3 to 0.5% of healthy individuals and remains usually asymptomatic. Variations of the superior vena cava should be considered in venous catheterization and other procedures such as implantation of pacemaker and ICD systems as well as port catheter insertion. In re-synchronization systems, persistent left superior vena cava can be an obstacle for cannulation of the coronary sinus and placement of a transvenous left ventricular lead.

Detection of coronary microembolisation by Doppler ultrasound during percutaneous coronary interventions

OBJECTIVE

To validate an intracoronary Doppler ultrasound device for high intensity transient signals (HITS) detection and to assess the incidence of HITS during percutaneous coronary intervention (PCI).

METHODS AND RESULTS

In an in vitro model, particle count and number of HITS detected by an intracoronary 0.014 inch Doppler wire were closely correlated (r = 0.97, p < 0.001). In the clinical study, 32 patients (mean (SD) age 61 (11) years; 23 men, nine women) with coronary artery disease were treated with balloon dilatation and stent implantation for a single vessel stenosis. In these patients HITS were detected during PCI in 84% (27 of 32). Reproducibility (r = 0.99, p < 0.001) and interobserver agreement (r = 0.84, p < 0.001) of HITS counts were significant. The number of HITS after stent implantation was significantly higher than after balloon dilatation (11 (7) v 2 (4), p < 0.001). Postprocedural coronary flow velocity reserve (CFVR) was < 2.0 in 55% (16 of 29) of all patients after balloon dilatation and < 2.0 in 23% (six of 26) after stent implantation. The number of HITS after stent implantation did not differ significantly between patients with CFVR < 2.0 and patients with CFVR > or = 2.0 (12 (8) v 10 (7), not significant).

CONCLUSIONS

Embolic particles can be detected as HITS by an intracoronary Doppler ultrasound device. Coronary microembolism is often observed during PCI, especially after stent implantation. However, the incidence of HITS alone does not explain a reduced CFVR after PCI.

[Cardiopulmonary monitoring in gastroenterological and renal emergencies]

Predominantly elderly and multimorbide patients require frequently intensive care observation and treatment due to acute gastrointestinal and renal disease. Manifest circulatory and rhythm instability, acute heart failure and severe metabolic or electrolyte derangements present indications for submission to a critical care unit. Stabilization of vital functions, control of specific therapeutic procedures (e. g. renal replacement therapy), and early recognition of secondary complications belong to the tasks of intensive care. Beyond a baseline monitoring available procedures comprises a broad spectrum from pulseoxymetrie to pulmonary artery catheter monitoring depending of the need of the individual patient.

Mechanische Herz-Kreislauf-Unterstützung in der Kardiologie

One out of 13 patients with an acute myocardial infarction is endangered of cardiogenic shock. In addition, acute valvular leakage, shunt vitiae, and acute myocarditis can lead to acute myocardial failure. As a therapeutic option, mechanical assist devices offer cardiac support and hemodynamic stabilization under these circumstances. The following minimal-invasive devices are used in cardiology and intensive care medicine: intra-aortic balloon pulsation (IABP), intra-vascular axial screw pumps, extra-corporal centrifugal pumps with and without additional membrane oxygenator. The IABP improves left ventricular function by a systolic reduction of the after-load, and an increase of diastolic blood pressure dependent on myocardial function. In contrast, axial screw pumps and centrifugal pumps can provide circulatory support independently of myocardial function. Mechanical assist devices can prevent irreversible damage not only by offering a reduction of myocardial work load, but also by improving organ perfusion in cardiogenic shock situations. Another indication for mechanical circulatory support depicts high-risk coronary angioplasty if the left ventricular ejection fraction is severely reduced or the target vessel supplies more than 50 % of vital myocardium. In case of irreversible heart failure, turbine pumps or centrifugal pumps offer a stabilization for the patient's transfer to a cardiac surgery center. They can also be used for bridging to heart transplantation in acute situations. Technical improvements will enhance the use of mechanical assist devices in the near future. Especially the development of portable emergency devices will enrich therapeutic possibilities in cardiology and intensive care medicine.

Transarterial aortic valve replacement with a self expanding stent in pigs

OBJECTIVES

To evaluate the feasibility of percutaneous aortic valve replacement without cardiac arrest in animal experiments.

METHODS

A self expanding nitinol stent, containing pulmonary valves from pigs in its proximal part, was implanted in six pigs (94-118 kg) by means of a 25 French catheter through the left subclavian artery under guidance of fluoroscopy and transoesophageal echocardiography. During stent deployment the original aortic valve was pushed against the aortic wall by the self expanding force of the stent while the new valve was expanded.

RESULTS

It was possible to replace the aortic valve in the beating heart in four pigs (67%) with no complication or relevant drop in blood pressure. The procedure failed in two pigs (33%) due to dysfunction of the catheter device in one case and to problems with correct positioning in the left ventricular outflow tract in the other. After successful stent valve implantation, dopamine was infused in doses of 5 microg/kg/min, 10 microg/kg/min, and 15 microg/kg/min. Cardiac output increased from 4.4 to 8.8 l/min and the mean arterial pressure rose from 79 to 105 mm Hg. The maximum peak to peak pressure gradient across the valve carrying stent reached a maximum of 8 mm Hg under dopamine infusion. All pigs were killed six hours after transvascular aortic valve replacement. The chest was opened, and the left ventricle and the ascending aorta were carefully inspected. There were no signs of malfunction of the implant, of damage of the aortic vessel wall, or of obstruction of the coronary ostia.

CONCLUSIONS

Percutaneous aortic valve replacement with a self expanding nitinol stent in the beating heart is possible. The device was safe under pharmacological stress test. After successful chronic animal experiments, this concept may become a feasible option for treating patients with relevant aortic valve disease but where open heart surgery would be risky.

Recovery of impaired microvascular function in collateral dependent myocardium after recanalisation of a chronic total coronary occlusion

OBJECTIVE

To assess the potential for recovery of impaired microvascular function in collateral dependent myocardium after recanalisation of a chronic total coronary occlusion and the determinants of this recovery.

PATIENTS AND DESIGN

120 patients underwent a successful recanalisation of a chronic total coronary occlusion (duration > 2 weeks) and a follow up angiography after a mean (SD) of 5.0 (1.2) months. The coronary flow velocity reserve (CFVR) and the fractional flow reserve were measured after recanalisation and at follow up. Global and regional left ventricular (LV) function were analysed by quantitative angiography.

RESULTS

Microvascular dysfunction, defined by a CFVR < 2.0 and a fractional flow reserve > or = 0.75, was observed in 55 (46%) patients after recanalisation. Microvascular function improved during follow up in 24 (20%). The CFVR increased during follow up from 2.01 (0.58) to 2.50 (0.79) (p < 0.001), due to a decrease in basal average peak velocity from 30.7 (14.9) cm/s to 25.5 (13.3) cm/s (p = 0.001). Improved microvascular function was associated with an improved regional LV function, shown by a correlation between increased wall motion severity index and increased CFVR (r = 0.38, p = 0.003). The major determinant of microvascular dysfunction at baseline was the presence of diabetes mellitus (odds ratio 4.3, 95% confidence interval 1.8 to 10.2), which remained so at follow up (odds ratio 4.1, 95% confidence interval 1.3 to 13.4). Improvement of LV function was not impaired by the presence of microvascular dysfunction after recanalisation.

CONCLUSIONS

The frequently observed microvascular dysfunction after recanalisation of a chronic total coronary occlusion is a transient phenomenon in most patients and is influenced by the presence of diabetes mellitus. It does not impede the recovery of LV function. Improved regional LV function is associated with improved microvascular function.

[Mobilization of stem cells by granulocyte colony-stimulating factor for the regeneration of myocardial tissue after myocardial infarction]

BACKGROUND AND OBJECTIVE

Animal data suggest that mobilized bone marrow cells (BMC) may contribute to tissue regeneration after myocardial infarction (MI). However the safety, feasibility and efficacy of treatment with granulocyte colony-stimulating factor (G-CSF) to mobilize BMC after acute myocardial infarction in patients is unknown. We analysed cardiac function and perfusion in 5 patients who were treated with G-CSF in addition to standard therapeutical regimen.

METHODS AND RESULTS

48 h after successful recanalization and stent implantation in 5 patients with acute MI, the patients received 10 micro g/kg bodyweight/day G-CSF subcutaneously for a mean treatment duration of 7.6+/-0.5 days. Peak value of CD34 (+) cells, a multipotent subfraction of bone marrow cells, was reached after 5.0+/-0.7 days. After 3 months of follow-up global left ventricular ejection fraction (determined by radionuclid-ventriculography) increased significantly from 42.2+/-6.6 % to 51.6+/-8.3 % (P<0.05). The wall motion score and the wall perfusion score (determined by ECG gated SPECT) decreased from 13.5+/-3.6 to 9.9+/-3.5 (P<0.05) and from 9.6+/-2.9 to 7.0+/-4.5 (P<0.05), respectively, indicating a significant improvement of myocardial function and perfusion. No severe side effects of G-CSF treatment could be observed. Malignant arrhythmias were not observed either.

CONCLUSION

In patients with acute MI, treatment with G-CSF to mobilize BMC appears to be well tolerable under clinical conditions. Improved cardiac function and perfusion may be attributed to BMC-associated promotion of myocardial regeneration and neovascularization.

Cardiac remodelling in end stage heart failure: upregulation of matrix metalloproteinase (MMP) irrespective of the underlying disease, and evidence for a direct inhibitory effect of ACE inhibitors on MMP

OBJECTIVE

To investigate matrix metalloproteinases (MMP-2 and MMP-9) in heart failure caused by ischaemic and idiopathic dilated cardiomyopathy, and the impact of angiotensin converting enzyme (ACE) inhibition on MMP.

DESIGN AND MAIN OUTCOME MEASURES

MMP were extracted from myocardium of patients with heart failure (coronary artery disease, n = 13; idiopathic dilated cardiomyopathy (IDCM), n = 16) and from controls (n = 6). The active form of MMP-2 and MMP-9 was measured by enzyme linked immunosorbent assay; activity of MMPs by zymography; mRNA expression of MMPs by reverse transcriptase polymerase chain reaction.

RESULTS

Active MMP-9 was significantly increased in coronary artery disease (mean (SD) 1.6 (0.35) ng/ml) and IDCM (2.11 (0.54) ng/ml) in comparison with controls (0.53 (0.15) ng/ml). Increased MMP-2 was only found in IDCM (3.68 (0.41) ng/ml). There were corresponding increases in MMP activity but no upregulation of mRNA expression was found. The ACE inhibitors captopril and ramiprilate inhibited MMP-2 and MMP-9 activity in vitro (inhibitory capacity (IC50), in mmol/l: MMP-2: captopril 2.0 (0.16), ramiprilate 2.1 (0.3); MMP-9: captopril 1.65 (0.18), ramiprilate 2.0 (0.3)). Lisinopril inhibited MMP-9 significantly but did not inhibit MMP-2 in vitro (IC50 MMP-2: 7.4 (0.88); MMP-9: 7.86 (2.23)). Inhibition of MMP activity by ACE inhibitors was blunted by zinc excess.

CONCLUSIONS

Upregulation of MMP-9 activity is common in the failing myocardium, independent of the underlying disease. Missing upregulation of transcription suggests that activation of latent forms of MMP is the source of increased MMP activity, rather than increased de novo synthesis. Some ACE inhibitors may influence MMP activity by a direct effect.

[Coronary flow velocity reserve and collateral resistance after recanalization of chronic total coronary occlusions and periprocedural CK and cTNI elevation]

After recanalization and stenting of chronic total coronary occlusions (TCO), a reduced coronary flow velocity reserve (CFVR) and rise in collateral resistance (R(Coll)) is frequently observed. Coronary microembolization may account for these observations. In 86 patients (age 64+/-10 years; 77 men, 9 women) with TCO (duration >4 weeks), PTCA was performed with successful stent implantation in all lesions. Before PTCA, viable myocardium was detected by stress echocardiography or nuclear imaging techniques. By simultaneously measuring coronary Doppler flow velocity and pressure before and after PTCA, CFVR and R(Coll) were calculated. Over a period of 24 hours after intervention, creatine kinase (CK; upper limit of normal [ULN] for women 1.17 micromol/L/s, for men 1.33 micromol/L/s) and cardiac troponin I (cTNI; threshold 0.1 ng/mL) were studied. CFVR was <2 in 48% of all patients. A rise in R(Coll) was observed in 83% of all patients. The incidence of CK and/or cTNI elevation was only observed in 10% of all patients. These patients with CK and/or cTNI elevation did not show a significant difference of CFVR and rise in R(Coll) as compared with patients without CK and cTNI elevation. CFVR or rise in R(Coll) did not correlate with CK elevation. Coronary microembolization is not a likely cause of reduced CFVR and increased R(Coll) after PTCA of TCO. Other factors such as microvascular dysfunction and autoregulatory changes in collateral function may account for these observations.

Perkutane Ballondilatation einer umschriebenen Subaortenstenose

Discrete subaortic stenosis is an uncommon congenital cardiac disorder in which the left ventricular outflow tract is narrowed. We report about the diagnostic procedures and the successful balloon dilatation of a 49-year old, highly symptomatic male patient suffering from discrete subvalvular aortic stenosis.

[Afterload and blood pressure amplitude in dilated cardiomyopathy]

The beat-to-beat variability of the diastolic blood pressure induces small variations in the afterload of the left ventricle. These variations influence myocardial contractility, and thus blood pressure amplitude. We assessed the interdependence of blood pressure and changes in the afterload. We continuously recorded blood pressure (duration 200 s, at rest) in 20 patients with dilated cardiomyopathy (ejection fraction 32 +/- 13%, left ventricular diameter 67 +/- 8 mm) and in 20 healthy volunteers. Interbeat intervals, diastolic pressures, systolic pressure amplitudes and mean slopes of systolic pressure amplitudes were measured. Correlation coefficients (r) were calculated to assess the interdependence of blood pressure amplitudes/mean systolic slopes and the preceding diastolic pressures/interbeat intervals, respectively. In healthy volunteers we found a strong interdependence between blood pressure amplitude and the preceding diastolic pressures (r = 0.62 +/- 0.21 and 0.47 +/- 0.22). Higher diastolic pressures were followed by higher blood pressure amplitudes, and by steeper slopes of the systolic peaks. In patients with dilated cardiomyopathy, such interdependence was significantly lower (r = 0.33 +/- 22 and r = 0.28 +/- 0.35), and in patients with severely reduced left ventricular function (ejection fraction < 32%) was only marginal (r = 0.23 +/- 0.27 and 0.21 +/- 0.44, respectively). The forces of the isovolumetric contraction necessary to initiate the ejection phase of the left ventricle depend on the afterload, i.e. on the diastolic pressure. The responses of amplitude and slope of the systolic blood pressure to small changes in the afterload make it possible to assess left ventricular contractility. The latter is impaired in dilated cardiomyopathy.

[Modified interaction of blood pressure and heart rate in idiopathic dilated cardiomyopathy]

BACKGROUND

Neurovegetative and haemodynamic changes impact on the regulation pattern of blood pressure and heart rate in patients with heart failure. We studied these patterns and their interactions in patients with idiopathic dilated cardiomyopathy (IDC) and in healthy subjects (REF).

METHODS

We continually measured the heart rate and blood pressure (Portapres device) in twenty-five supine IDC patients (age: 51 +/- 13 y; left ventricular end-diastolic diameter 67 +/- 11 mm; ejection fraction 30 +/- 11%) and in twenty-seven REF (age: 50 +/- 11 y) Recording time was 30 minutes. The heart rate (HR) of each beat and the systolic blood pressure (SYS) of the subsequent beat were measured. Code numbers (symbols) were assigned to the beat-to-beat changes in HR and SYS (increase: 1; decrease: 0). The frequencies of the symbols sequences of three successive beats were counted. In this way we obtained a matrix consisting of eight (two to the power of three) HR and SYS combinations: 000, 100, 010, 001, 111, 110, 011 and 101. We then counted the frequencies of the different combinations of the symbol sequences in HR and SYS (2(3) x 2(3) = 64 combinations). The relative frequencies of symbol patterns appearing in HR, SYS and in the combined analysis of HR and SYS, were compared for IDC and REF using the T-test for independent samples.

RESULTS

Significant differences were seen between IDC and REF. The HR patterns 101 and 010 were more frequent in IDC than in REF patients (11.1 +/- 4.7 vs. 7.7 +/- 2.9%, p = 0.003, and 16.1 +/- 6.3 vs. 11.7 +/- 4.9%, p = 0.008). This finding was even more marked in the analysis of the SYS patterns 101 and 010 (11.0 +/- 7.4 vs. 8.2 +/- 2.9%, p < 0.001, and 11.6 +/- 7.4 vs. 5.4 +/- 2.7%, p < 0.001). Non-alternating patterns were more frequent in REF (e.g. 000HR & 111SYS: 4.6 +/- 3.3 vs. 2.9 +/- 2.4%, p = 0.03).

CONCLUSIONS

We demonstrated significant interaction of the regulation patterns of blood pressure and heart rate, as also their interactions in IDC. Opposed changes in HR and SYS mediated by the baroreflex, became superimposed by alternans phenomena in IDC. The pattern analysis of changes in HR and SYS detects these disturbances of neurovegetative short-term control.

Exercise capacity and Doppler pressure measurements in symptomatic peripheral arterial obstructive disease

BACKGROUND

Doppler pressure measurements are a useful diagnostic tool in peripheral arterial obstructive disease. The aim of our study was to determine whether these pressure values do predict the degree of impairment of the walking capacity in symptomatic patients.

PATIENTS AND METHODS

We compared the claudication distances (CDI: initial claudication distance, CDA: absolute claudication distance) of 939 patients (63 +/- 11 years) with stable intermittent claudication (Fontaine IIb) with the ankle pressure values at rest (APR) and after exercise (APE), with the ankle/brachial pressure index at rest (ABIR) and after exercise (ABIE), and with the ratio (ABIRATIO = ABIE/ABIR). Ankle systolic pressures were obtained using an 8 MHz Doppler probe. CD was measured by a treadmill test at constant-load conditions (3 km/hr; inclination 12%). Brachial systolic pressures were obtained using an automated blood pressure monitor. The values of the objectively worse leg were correlated with CDI and CDA.

RESULTS

Low Doppler pressure values were not accompanied by significantly shorter walking distances in symptomatic patients. The resting pressure values (APR, ABIR) did not correlate with the claudication distances (CDI: 54 +/- 31 m; CDA: 87 +/- 41 m). For the exercise values (APE, ABIE), even a very slight inverse correlation with the claudication distances was found. In addition, the correlation between the pressure index ratio and the walking distances (ABIRATIO vs. CDI: r = -0.25, p < 0.01; ABIRATIO vs. CDA: r = -0.20, p < 0.01) was inverse, too, but slightly more pronounced.

CONCLUSIONS

In patients with intermittent claudication the ankle artery pressures and the indices derived from these pressure values do not predict the walking distance. Therefore, the decision for angioplasty or bypass surgery should be made with regards to the impairment of quality of life rather than Doppler pressure values.

[Occlusion of the arteries of the fingers after hyperextension trauma]

Acute occlusion of digital arteries due to a sport injury A 33 year old female patient with acute ischaemia of the fingers I-II of the right hand was admitted to our emergency unit. She reported that this complete ischaemia had shortly occurred after a sport injury due to an extreme hyperflexion of the right hand in a volleyball match. Four days after this trauma she felt pain and paraesthesia in the right hand. Circular areas of ischaemia were developed with skin colour change to grey and dark blue. The primary measure of the blood pressure by doppler analysis showed no signals in the first and second finger. Initially she received 500 mg Aspirin by intravenous injection. The full therapeutic dose of LMWH related to the weight of the patient was given. On the basis of the short time interval between the occurrence of the symptoms and admission of the patient we decided to perform a so called retrograde intravenous injection. The aim of this therapy was the intraarterial lysis and reperfusion. The blood pressure in all fingers were nearly normal after three days. Daily intravenous transfusion of prostaglandin were given additionally. Necrosis could be prevented as a result of our treatment over seven days. At the end of our therapy only the skin epithelium of the second finger was slightly raised and showed a tendency to desquamation. All other fingers occurred in a normal colour.

High frequency intra-QRS signals in idiopathic dilated cardiomyopathy

We extracted and quantified high frequency intra-QRS signals in idiopathic dilated cardiomyopathy (IDC). In IDC the analysis of late potentials in the terminal QRS complex often fails in predicting clinical events because of intraventricular conduction abnormalities and the absence of a circumscribed arrhythmogenic substrate. Therefore, new approaches are required to assess the electrical state of the myocardium. We investigated 21 patients suffering from IDC with (n = 14) and without (n = 7) bundle branch block. High resolution 31 lead magnetocardiograms were filtered with a 67 point 4th order Savitzky-Golay filter. The difference of the measured and filtered signals was calculated (67-200 Hz). The spatio-temporal properties and the areas under the curves of the resulting high frequency intra-QRS signals (IQCs) were studied. We detected IQCs in all patients. The patients had individual patterns regarding the temporal and spatial properties of the IQCs during depolarisation. The IQCs predominantly appeared in the initial portion of the QRS. The ratios of the areas under the curves of the IQCs and the measured signals were linearly correlated to the left ventricular enddiastolic diameter (r = 0.71, significance 0.0012). In IDC the ventricular depolarization is accompanied by individual spatial and temporal patterns of high frequency intra-QRS signals. They can be studied non-invasively from body surface mapping data with the algorithm used in this study. This provides access to the assessment of the electrical status in patients with IDC.

Collateral function in chronic total coronary occlusions is related to regional myocardial function and duration of occlusion

BACKGROUND

Collateral circulation can maintain myocardial function and viability in chronic total coronary occlusion (TCO). The present study evaluates the relation of myocardial function and duration of occlusion to collateral function.

METHODS AND RESULTS

A total of 50 patients underwent a successful recanalization of a TCO (>4 weeks' duration). Collateral function was assessed by intracoronary Doppler and pressure recordings before the first balloon inflation and after PTCA had been completed. Collateral function was assessed by Doppler- (CFI(D)) and pressure-derived collateral flow indices (CFI(P)), as well as indices of collateral (R(Coll)) and peripheral resistance (R(P)). Patients with normokinesia had lower R(Coll) (4.9+/-2.5 versus 11.8+/-8.2 mm Hg. cm(-1). s(-1); P=0.033) and lower R(P) (3.8+/-1.9 versus 6.1+/-4.1 mm Hg. cm(-1). s(-1); P=0.031) than those with akinesia. Patients with akinesia and a TCO duration of </=3 months had the highest R(Coll) and R(P), whereas those with akinesia and a longer TCO duration had similar collateral function as patients with normokinesia. After PTCA, CFI(D) and CFI(P) decreased from 0.37+/-0.20 to 0.21+/-0.17 (P<0.001) and from 0.44+/-0.12 to 0.36+/-0.11 (P<0.001), respectively, with an increase in R(Coll) of 139+/-128% (P<0.001) and R(P) by 65+/-99% (P=0.003). This attenuation of collateral function was less pronounced with epicardial collaterals than with intramyocardial collaterals.

CONCLUSIONS

Collateral function was better in patients with TCO and normal regional function than in those with impaired regional function. In the latter group, collateral function improvement was time dependent. After recanalization, the recruitable collateral function was attenuated because of an increase of R(Coll) and R(P).

Reversibility of coronary endothelial vasomotor dysfunction in idiopathic dilated cardiomyopathy: acute effects of vitamin C

In patients with idiopathic dilated cardiomyopathy, endothelium vasomotor function is disturbed. Increased oxidative stress and the consecutive formation of oxygen free radicals have been implicated as one possibility for this observation, suggesting that nitric oxide (NO) is inactivated by oxygen free radicals. We tested the hypothesis that the antioxidant, vitamin C, may improve endothelial function in idiopathic dilated cardiomyopathy. In 11 patients, the endothelium-dependent vasomotor response of the left anterior descending coronary artery to intracoronary acetylcholine (ACh) infusion (1/2 x 10(-6) mol/L, 1/4 x 10(-5) mol/L; respectively) was determined before and immediately after intravenous infusion of 3 g of vitamin C. Coronary cross-sectional diameter was obtained by quantitative coronary angiography, average peak velocity was measured by an intracoronary Doppler flow wire, and coronary blood flow (CBF) was calculated. Maximum cross-sectional diameter was determined after administration of nitroglycerin. Dose-dependent ACh showed a decrease in cross-sectional diameter (-5% to -7%, p <0.05) and an increase in average peak velocity (+16% to +25%, p <0.05); the CBF was unchanged (+1% to -2%, p = NS). After vitamin C infusion, the cross-sectional diameter increased in a dose-dependent manner from +11% to +15%, the average peak velocity increased from +20% to + 41% (p <0.05), and the CBF increased from +38% to + 82% (p <0.01, p <0.001, respectively). Thus, patients with idiopathic dilated cardiomyopathy had endothelial dysfunction, and administration of vitamin C reversed endothelium-dependent dysfunction.