Effects of simvastatin on pulmonary fibrosis, pulmonary hypertension and exercise capacity in bleomycin-treated rats

AIM

Pulmonary fibrosis is often complicated by pulmonary hypertension. Statins reduce fibroblast activity in vitro and pulmonary hypertension in vivo. We investigated whether Simvastatin exerts beneficial effects on pulmonary fibrosis and pulmonary hypertension in Bleomycin-treated rats in vivo.

METHODS

Rats were randomly assigned to controls, Bleomycin, Bleomycin plus Simvastatin from day 1 to 28 and Bleomycin plus Simvastatin from day 13 to 28. 28 days after Bleomycin instillation, right ventricular systolic pressure (RVSP), right ventricular mass (RV/(LV+S)), right ventricular and circulating brain natriuretic peptide (BNP) levels were determined to assess pulmonary hypertension. Pulmonary hydroxyproline content (HPC), pulmonary connective tissue growth factor (CTGF) transcription and lung compliance (LC) were analysed to characterize pulmonary fibrosis. Exercise capacity was determined by treadmill tests.

RESULTS

Compared with controls, Bleomycin increased RVSP, RV/(LV+S), BNP levels, HPC and CTGF transcription and decreased LC significantly. Simvastatin administered from day 1 to 28 normalized all these parameters. Simvastatin administered from day 13 to 28 had no effect on HPC and LC, but reduced RV/(LV+S) significantly and induced a strong trend to lower RVSP and BNP levels. Exercise capacity was reduced by Bleomycin. Simvastatin significantly improved exercise intolerance in both treatment groups.

CONCLUSIONS

Simvastatin prevents the development of pulmonary fibrosis, but fails to attenuate already established pulmonary fibrosis. In contrast, it ameliorates pulmonary hypertension and thereby exercise capacity in the prevention and the treatment group regardless of its effects on pulmonary fibrosis. Whether statins are a treatment option in humans with pulmonary fibrosis needs to be investigated by further study.

Polysomnography underestimates altered cardiac autonomic control in patients with obstructive sleep apnea

BACKGROUND

Repetitive nocturnal sympathetic activation during episodes of apnea and postapneic hyperventilation increases cardiovascular risk. The effects of hypopnea and non-apneic, non-hypopneic intervals before and after hypopnea/apnea on sympathico-vagal balance have not been assessed yet.

HYPOTHESIS

Hypopnea and non-apneic, non-hypopneic intervals before and after hypopnea/apnea cause increased sympathetic activity when compared to normal respiration in nonREM stages 2–4.

METHODS

A total of 34 patients were studied using in-laboratory polysomnography including continuous ECG recording. Absolute spectral power of heart rate variability in the very low (VLF), low (LF), and high frequency (HF) bands and low frequency to high frequency power ratio (LF/HF ratio) were analyzed during apnea, hypopnea, and during the pre- and post-phases of such respiratory episodes and compared to spectral powers during normal respiration in nonREM sleep 2–4.

RESULTS

Patients with hypopnea and/or obstructive apnea showed higher power of VLF and the LF/HF ratio in intervals of hypopnea/apnea and in non-apneic, non-hypopneic intervals before and after hypopnea/apnea compared to normal respiration in nonREM stages 2–4.

CONCLUSION

The effect of sleep-disordered breathing on alteration of autonomic tone in patients with hypopnea and obstructive apnea is more severe than estimated by conventional polysomnographic assessment of apnea and hypopnea. Patients with sleep apnea show a sympathetic overdrive not only during phases of hypopnea and obstructive apnea but also in non-apnea, non-hypopnea intervals before and after hypopnea, and obstructive apnea.

Impaired cardiac autonomic control relates to disease severity in pulmonary hypertension

Pulmonary arterial hypertension (PAH) results in chronic right heart failure, which is associated with an increase in sympathetic tone. This may adversely affect cardiac autonomic control. We investigated the changes in cardiac autonomic nervous activity in relation to disease severity in patients with PAH. In 48 patients with PAH (median World Health Organization class III, pulmonary artery pressure 52+/-14 mmHg, pulmonary vascular resistance 1,202+/-718 dyn x s x cm(-5), cardiac index 2.0+/-0.8 L x min(-1) x m(-2)) and 41 controls, cardiac autonomic nervous activity was evaluated by measurement of heart rate variability (HRV) and baroreflex sensitivity. All patients underwent cardiopulmonary exercise testing (peak oxygen uptake 13.2+/-5.1 mL x kg(-1) x min(-1), minute ventilation/carbon dioxide production slope 47+/-16). In patients with PAH, spectral power of HRV was reduced in the high-frequency (239+/-64 versus 563+/-167 ms2), low-frequency (245+/-58 versus 599+/-219 ms2) and very low-frequency bands (510+/-149 versus 1106+/-598 ms2; all p<0.05). Baroreflex sensitivity was also blunted (5.8+/-0.6 versus 13.9+/-1.2 ms x mmHg(-1); p<0.01). The reduction in high-frequency (r = 0.3, p = 0.04) and low-frequency (r = 0.33, p = 0.02) spectral power and baroreflex sensitivity (r = 0.46, p<0.01) was related to the reduction in peak oxygen uptake. Patients with PAH have a marked alteration in cardiac autonomic control that is related to exercise capacity and may, therefore, serve as an additional marker of disease severity.

Combining inhaled iloprost with bosentan in patients with idiopathic pulmonary arterial hypertension

Addition of inhaled iloprost to bosentan may have beneficial effects in patients with idiopathic pulmonary arterial hypertension (IPAH). A multicentre, open, randomised, controlled trial was performed to assess the safety and efficacy of inhaled iloprost in patients with IPAH who had already been treated with bosentan. The trial was terminated early after a futility analysis predicted failure with respect to the predetermined sample size. At that time, 40 patients were randomised to receive either bosentan alone (control group) or bosentan plus inhaled iloprost (combination group) for a 12-week period. The primary end-point, change in 6-min walking distance, was not met (mean changes +1 m and -9 m in the control and combination group, respectively). These results may have been skewed by three outliers in the iloprost group who presented with severe clinical worsening. None of the secondary end-points including functional class, peak oxygen uptake, and time to clinical worsening differed significantly between groups. The current study failed to show a positive effect of adding inhaled iloprost to bosentan in idiopathic pulmonary arterial hypertension patients. Further studies involving larger sample sizes and long-term follow-up are needed to determine the efficacy of adding inhaled iloprost to bosentan in patients with idiopathic pulmonary arterial hypertension.

[Pulmonary hypertension in hereditary haemorrhagic teleangiectasia (Rendu-Osler-Weber disease). Progression over 10 years]

HISTORY

10 years ago a now 49-year-old woman with Render-Osler-Weber disease showed unspecific symptoms of nausea, and general unwellness. Pulmonary manifestation of the disease was accompanied by pulmonary hypertension.

INVESTIGATION

Teleangiectasia of the tongue and pharynx as well as of the mucosa of mouth and nose were observed. Fixed-splitting of the second heart sound with accentuated pulmonary component and a 2/6 systolic murmur over the tricuspid valve were heard. In addition, a murmur was heard dorsal over the right lung's lower lobe. Apart from minor oedema of both ankles, the physical status was not remarkable. Echocardiography showed dilatation of the right ventricle and a minor regurgitation of the tricuspid valve. The computed tomography showed dilatation of the pulmonary arteries as well as an arteriovenous malformation in the right lower lobe. Right-heart catheterisation revealed elevated pulmonary pressure. THERAPY AND FOLLOW-UP: Initial treatment with a calcium channel blocker proved insufficient and was changed to inhalative, and later to oral prostanoids. Under this treatment the cardiopulmonary state was stabilised, but episodes of epistaxis were increased. Two years after readjustment of the medication to a dual endothelin receptor antagonist, the cardiopulmonary state remains stable without significant haemorrhagic complications.

CONCLUSION

Prostanoid treatment in patients with Render-Osler-Weber disease and additional pulmonary hypertension can lead to an increased risk of haemorrhagic complications. Treatment with newer medications, such as endothelin receptor antagonists, seems indicated as successfully illustrated in our case.

Assessment of the vasodilator response in primary pulmonary hypertension. Comparing prostacyclin and iloprost administered by either infusion or inhalation

AIMS

To directly compare the differential effects of oxygen, prostacyclin and iloprost (aerosolized and intravenous) in primary pulmonary hypertension.

METHODS AND RESULTS

Twenty-one patients with severe primary pulmonary hypertension underwent right heart catheterization following oxygen inhalation, inhalation of aerosolized iloprost, intravenous prostacyclin or intravenous iloprost. The stability of the iloprost solution was tested for up to 4 weeks. Oxygen slightly decreased pulmonary vascular resistance. Intravenous prostacyclin (7.2+/-3.4 ng kg(-1) min(-1)) reduced pulmonary (1772+/-844 vs 1325+/-615 dyn s cm(-5), P<0.001) and systemic vascular resistance, and arterial and right atrial pressure, while cardiac output increased. Iloprost inhalation diminished pulmonary (1813+/-827 vs 1323+/-614 dyn s cm(-5), P<0.001) and systemic vascular resistance, and pulmonary artery (58+/-12 vs 50+/-12 mmHg,P<0.001) and right atrial pressure, while cardiac output increased. With intravenous iloprost (1.2+/-0.5 ng kg(-1) min(-1), n=8) a decrease in pulmonary (2202+/-529 vs 1515+/-356 dyn s cm(-5), P<0.05) and systemic vascular resistance and right a trial pressure occurred while cardiac output increased. Iloprost solution remained stable for 33 days while losing <10% (4 degrees C) of its active drug concentration.Conclusions Intravenous iloprost and prostacyclin have very similar haemodynamic profiles. In contrast, only inhaled iloprost exerted selective pulmonary vasodilation, reducing pulmonary vascular resistance and pulmonary artery pressure without systemic vasodilation. The longer half-life and extended stability despite lower costs render iloprost an attractive alternative to chronic prostacyclin treatment in primary pulmonary hypertension.

Big endothelin-1 and endothelin-1 plasma levels are correlated with the severity of primary pulmonary hypertension

STUDY OBJECTIVES

Primary pulmonary hypertension (PPH) is a rare disease of unknown etiology that is characterized by a poor prognosis. This study was undertaken to investigate possible correlations between endothelin (ET)-1 and big ET-1 plasma levels and the severity of PPH.

PATIENTS

Sixteen consecutive patients with PPH were included.

INTERVENTIONS

Hemodynamics of patients with PPH were measured by right-heart catheterization, and a 6-min walk test was performed.

MEASUREMENTS

Plasma levels of the biologically active peptide ET-1 and its precursor big ET-1 were determined in blood samples from the pulmonary artery, peripheral artery, and peripheral vein by radioimmunoassay.

RESULTS

A strong correlation was shown between pulmonary vascular resistance, mean pulmonary artery pressure, cardiac output, cardiac index, 6-min walk data, and elevated plasma levels of big ET-1 as well as mature ET-1 plasma levels at all sites of blood sampling (p < 0.01 and p < 0.05, respectively).

CONCLUSIONS

Levels of circulating ET-1 might become a prognostic marker for patients with PPH and serve as a tool for the selection of patients who may benefit from treatment with ET-receptor antagonists.

Iloprost als inhalative bzw. intravenöse Langzeitbehandlung von Patienten mit Primärer Pulmonaler Hypertonie – Register der Berliner Arbeitsgruppe für Pulmonale Hypertonie –

Follow-up data for 81 consecutive patients with primary pulmonary hypertension (PPH) and pulmonary hypertension related to connective tissue diseases or liver cirrhosis, entered into a multicenter registry in Berlin between 1/96 and 11/99, are described. At entry into the registry the diagnosis of PPH was known for 22 +/- 32 months. Hemodynamically, these patients were characterized by a right atrial pressure of 8.6 +/- 5 mmHg, a mean pulmonary arterial pressure of 58.9 +/- 17 mmHg, a cardiac index of 1.8 +/- 0.6 l/min/m2 and a pulmonary vascular resistance of 1574 +/- 787 dyn x s x cm-5. In about one third of the patients, a restrictive and/or obstructive pulmonary physiology was found while the majority showed signs compatible with small airway disease. Furthermore, diffusion abnormalities were found in about 65% of the patients. When added to conventional medical therapy the treatment with inhaled or continuously infused prostanoids represents a major improvement in the treatment of patients with PPH. Aerosolized iloprost therapy was started in 51 patients and was continued for 12 and 24 months in 20 and 6 patients, respectively. This therapy was well tolerated without any significant changes in pulmonary function or signs of toxicity. About 25% of these patients had to be switched to continuous intravenous therapy due to progressive clinical and hemodynamic deterioration. About two thirds of these "rescue patients" could be stabilized on intravenous therapy and discharged from the hospital. Based on the currently available evidence, the continuous infusion of prostanoids represents an important part of the standard therapy in the treatment of patients with PPH. These first long-term data on inhaled iloprost therapy in this patient group illustrate the potential value of this well-tolerated and effective treatment within the concept of a differentiated treatment plan for patients with PPH. However, the true importance of prostanoid inhalation in comparison to continuous intravenous therapy in PPH remains to be determined in randomized controlled trials.

Impairment of ventilatory efficiency in heart failure: prognostic impact

BACKGROUND

Impairment of ventilatory efficiency in congestive heart failure (CHF) correlates well with symptomatology and contributes importantly to dyspnea.

METHODS AND RESULTS

We investigated 142 CHF patients (mean NYHA class, 2.6; mean maximum oxygen consumption [VO(2)max], 15.3 mL O(2) x kg(-1) x min(-1); mean left ventricular ejection fraction [LVEF], 27%). Patients were compared with 101 healthy control subjects. Cardiopulmonary exercise testing was performed, and ventilatory efficiency was defined as the slope of the linear relationship of V(CO(2)) and ventilation (VE). Results are presented in percent of age- and sex-adjusted mean values. Forty-four events (37 deaths and 7 instances of heart transplantation, cardiomyoplasty, or left ventricular assist device implantation) occurred. Among VO(2)max, NYHA class, LVEF, total lung capacity, and age, the most powerful predictor of event-free survival was the VE versus V(CO(2)) slope; patients with a slope </=130% of age- and sex-adjusted normal values had a significantly better 1-year event-free survival (88.3%) than patients with a slope >130% (54.7%; P<0.001).

CONCLUSIONS

The VE versus V(CO(2)) slope is an excellent prognostic parameter. It is easier to obtain than parameters of maximal exercise capacity and is of higher prognostic importance than VO(2)max.

Effects of iloprost inhalation on exercise capacity and ventilatory efficiency in patients with primary pulmonary hypertension

BACKGROUND

The continuous infusion of prostacyclin has been shown to improve exercise capacity and survival in patients with primary pulmonary hypertension (PPH). Inhalation of iloprost, a stable analog of prostacyclin, might be an alternative therapy for PPH, selectively acting on the pulmonary vascular bed through ventilation-matched alveolar deposition of the drug. We investigated the short-term effects of iloprost inhalation on exercise capacity and gas exchange in patients with PPH.

METHODS AND RESULTS

In 11 patients with PPH, we performed 2 consecutive cardiopulmonary exercise tests before and after the inhalation of 17 microgram of iloprost. Patients had marked pulmonary hypertension (mean pulmonary artery pressure 65 mm Hg), and inhalation resulted in a decrease in pulmonary vascular resistance (1509 versus 1175 dyne. s(-1). cm(-5), P<0.05). Arterial blood gases remained unchanged (PaO(2) 69.3 versus 66.8 mm Hg; PaCO(2) 29.6 versus 28.8 mm Hg). Iloprost significantly (P<0.05) improved exercise duration (379 versus 438 seconds), peak oxygen uptake (12.8 versus 14.2 mL. kg(-1). min(-1)), VE-versus-V CO(2) slope (58 versus 51.4).

CONCLUSIONS

The present data show that iloprost inhalation exerts pulmonary vasodilatation and improves symptoms and exercise capacity in patients with PPH. The data also suggest that iloprost inhalation is a suitable treatment for PPH. Whether these effects are maintained during long-term treatment and are paralleled by improvement in prognosis remains to be determined.

Relationship between impaired pulmonary diffusion and cardiopulmonary exercise capacity after heart transplantation

STUDY OBJECTIVES

Diffusion impairment and reduced performance in cardiopulmonary exercise testing (CPX) have been found in patients after heart transplantation. The pathogenesis of these abnormalities is unclear. In particular, the contribution of pulmonary interstitial changes has not yet been verified.

DESIGN

We analyzed pulmonary function tests, high-resolution CT (HRCT), echocardiography, left heart catheterization, and CPX in transplanted patients.

PATIENTS

Forty long-term survivors were studied at a median of 47 months (range, 12 to 89 months) after heart transplantation.

RESULTS

Diffusion was impaired in 40% (transfer factor for carbon monoxide) or 82.5% (carbon monoxide transfer coefficient) of the patients. Diffusion impairment was caused by a decreased diffusing capacity of the alveolar capillary membrane in 89% and/or by a decreased blood volume of the alveolar capillaries in 46% of cases. In five patients (12.5%), CT revealed interstitial lung changes. These patients did not have different values of diffusion capacity. Maximal oxygen uptake and ventilatory efficiency during exercise (minute ventilation/carbon dioxide output slope) were impaired in 92% and 46% of the cases, respectively.

CONCLUSIONS

Our data show that the diffusion abnormalities are caused by an impaired diffusion status of the alveolar capillary membrane. Interstitial changes detectable in HRCT were found not to be involved in this process. The reduced performance in CPX in our long-term survivors is caused by pulmonary perfusion abnormalities and low tidal volume, which is due to the deconditioning of respiratory muscle, rather than by interstitial changes or diffusion abnormalities.

[Glycogenosis type IV as a seldom cause of cardiomyopathy - report about a successful heart transplantation]

We report about a 17 year old male patient with a cardiomyopathy secondary to type IV glycogenosis (Andersens disease) and class II immunoglobulin deficiency who underwent cardiac transplantation. The patient first developed symptoms of heart failure at the age of twelve. The histologic diagnosis was cardiomyopathy secondary to glycogenosis. In addition, the patient suffered recurrent pulmonary infections and developed bronchiectases in the left lower lobe. This region was atelectatic since he was eleven. The patient did have two younger brothers who died of congestive heart failure at the age of nine and ten. Neither his parents nor anybody else of his relatives had a history of heart failure or glycogenosis. Since the patient suffered recurrent cardiac decompensations with the need for catecholamines he was accepted for cardiac transplantation although several relative contraindications to transplantation such as cachexia, myopathy, immunglobulin deficiency and bronchiectases had been present. The patient was transplanted successfully. The postoperative weaning from the respirator was markedly prolonged and complicated by pulmonary infection. Furthermore, mobilization was retarded. One year after transplantation, he is in a good condition without pulmonary or systemic infection. Right ventricular endomyocardial biopsies did not show recurrence of glycogenosis in the donor organ.

Acetylcholine but not sodium nitroprusside exerts vasodilation in pulmonary hypertension secondary to chronic congestive heart failure

BACKGROUND

Reduced endothelium-dependent vasodilation contributes to the development of pulmonary hypertension in chronic congestive heart failure (CHF). We investigated pulmonary endothelium-dependent and independent vasodilation in patients with CHF.

METHODS

We studied 42 patients with CHF (age 55 +/- 10, NYHA Classes II-III, left ventricular ejection fraction 27 +/- 10%, mean PAP 29 +/- 12 mmHg). The endothelial vasodilator capacity of pulmonary resistance vessels was assessed by the infusion of acetylcholine into a pulmonary artery branch while measuring the blood flow velocity with a Doppler flow wire. For comparison endothelium-independent vasodilation was measured with the response to sodium nitroprusside. The conductance vessel diameter (4.4 +/- 0.2 mm) was determined by intravascular ultrasound. Acetylcholine was administered at concentrations of 10(-6) to 10(-4) mol/l, sodium nitroprusside was administered at concentrations of 0.125 and 0.25 microg/kg per min. The effects on conductance vessel diameter were investigated in 12 patients by the measurement of diameter and flow velocity following the administration of acetylcholine and sodium nitroprusside.

RESULTS

Acetylcholine markedly increased blood flow velocity (+39 +/- 7% at 10(-4) mol/l; p < .05). This correlated with the baseline PAP (r = 0.58; p < .05) and pulmonary vascular resistance (r = 0.58; p < .05). Sodium nitroprusside caused a small increase in the flow velocity (5 +/- 2% at 0.125, 12 +/- 4% at 0.25 microg/kg per minute; p < .05) that was accompanied by systemic vasodilation. The conductance vessel diameter was unchanged after acetylcholine was administered and was only marginally decreased after the administration of sodium nitroprusside.

CONCLUSIONS

In CHF acetylcholine reveals preserved receptor-mediated endothelial vasodilation, that is positively correlated to pulmonary hypertension, and cannot be reproduced by sodium nitroprusside.

Ventilatory and diffusion abnormalities in long-term survivors after orthotopic heart transplantation

OBJECTIVE

To investigate the long-term development of pulmonary diffusion abnormalities after orthotopic heart transplantation (oHT).

DESIGN

Retrospective analysis of pulmonary function test results of different patient groups at different time intervals after oHT was performed.

PATIENTS

This investigation included 642 patients who had undergone oHT for chronic heart failure. Patients were grouped according to the time elapsed after transplantation (group 1: n = 164; age, 47 +/- 14 years; days after oHT, 324 +/- 101; group 2: n = 100; age, 48 +/- 15 years; days after oHT, 723 +/- 104; group 3: n = 106; age, 52 +/- 12 years; days after oHT, 1,092 +/- 98; group 4: n = 84; age, 51 +/- 13 years; days after oHT, 1,442 +/- 99; group 5: n = 61; age, 50 +/- 14 years; days after oHT, 1,819 +/- 105; group 6: n = 101; age, 53 +/- 12 years; days after oHT, 2,463 +/- 303; and group 7: n = 26; age, 54 +/- 14 years; days after oHT, 3,478 +/- 246). In 56 (group 8) of the 642 patients, follow-up measurements were performed with tests before and at two time points after oHT (6.5 +/- 1.7 and 12.5 +/- 9.3 months).

RESULTS

Of all patients, 39% showed restrictive and obstructive abnormalities with no differences between the groups. No significant differences in lung transfer factor for carbon monoxide (DLCO) were observed (61.2 vs 63.7 vs 65.5 vs 65.6 vs 64.5 vs 65.7 vs 67.6% predicted). Differences in transfer coefficient for carbon monoxide (Kco) were significant between group 1 and 4 (58.7 vs 64.1% predicted), and group 1 and 6 (58.7 vs 63.4% predicted). No differences occurred in the rate with which patients exhibited pathologic abnormalities for DLCO and KCO. After oHT, a marked reduction in diffusion capacity occurred in group 8. On follow-up, these measurements were only slightly restored in terms of the predicted DLCO percentage. No such improvement was observed in KCO or in the rate of pathologic changes for both DLCO and KCO. We conclude, therefore, that the impairment of diffusion does not improve even after a significant period has passed after the oHT. Whether this has any effect on symptoms and/or the prognosis for these patients is extremely unclear.

Impaired ventilatory efficiency in chronic heart failure: possible role of pulmonary vasoconstriction

BACKGROUND

Patients with chronic heart failure show impairment of ventilatory efficiency, defined as the relation between ventilation and carbon dioxide output. It is caused by ventilation of excess physiologic dead space. We hypothesized a role of active vasoconstriction in the increase of physiologic dead space, presumed to lead to alveolar hypoperfusion.

METHODS AND RESULTS

In 57 patients with chronic heart failure (New York Heart Association classification II through IV, ejection fraction 25.6%+/-10.4%) and 7 control subjects, gas exchange at rest and on exercise was compared with hemodynamic measurements and, in a subgroup of 15 patients, with endothelin-1, epinephrine, and norepinephrine levels in the pulmonary and systemic circulation. Ventilatory efficiency at rest (VE/VCO2 ratio) correlated with ventilatory efficiency on exercise (VE vs VCO2 slope). Impairment of ventilatory efficiency correlated strongly negative with exercise tolerance (maximal oxygen uptake: r = -0.67) and cardiac output (r = -0.66) and positive with pulmonary hypertension (mean pulmonary artery pressure: r = 0.69, pulmonary vascular resistance: r = 0.60). None of the vasoconstrictors correlated with reduction of ventilatory efficiency in the subgroup studied.

CONCLUSIONS

Impairment of ventilatory efficiency in chronic heart failure is correlated with resting pulmonary artery pressures and associated with the impairment of exercise capacity. An imbalance of pulmonary vascular tone probably leads to both pulmonary hypertension and alveolar hypoperfusion.

Relationship between haemodynamics and morphology in pulmonary hypertension. A quantitative intravascular ultrasound study

BACKGROUND

Intravascular ultrasound imaging of the pulmonary arteries has been demonstrated to be a reliable method of quantifying vessel diameter, luminal area and pulsatility. Simultaneous measurement of flow velocity and its response to vasodilators allows the relationship between morphology and functional compromise to be studied, especially endothelial dysfunction.

METHODS

In 51 patients (mean age = 49.8 +/- 12.6 years, 17 female) we performed right heart catheterization and simultaneous intravascular ultrasound of pulmonary artery branches. The patients were divided in two groups: group 1 with normal pulmonary artery pressure and pulmonary vascular resistance, and group 2 with pulmonary hypertension (peak pulmonary artery pressure > 30 mmHg and/or mean pulmonary artery pressure > 20 mmHg). Vessel wall and lumen were studied using a 2.9 F intravascular ultrasound catheter with a 30 MHz phased array transducer. Measurement of blood flow velocity was accomplished by a Doppler flow wire (0.018 inch). The maximal flow change during acetylcholine infusion (adjusted to 10(-6); 10(-5), and 10(-4) M concentration in the blood vessel) was measured.

RESULTS

There were no significant differences between groups 1 and 2 with respect to age (48.5 +/- 14.3 years vs 50.3 +/- 12.3 years; P = ns), gender (4 female/8 male vs 13 female/26 male; P = ns), luminal area of the vessel segment in which the intravascular ultrasound measurements were obtained (11.8 +/- 6.1 mm2 vs 16.7 +/- 14.3 mm2; P = ns), internal diameter (3.9 +/- 1.2 mm vs 4.2 +/- 1.7 mm; P = ns), and external diameter (6.1 +/- 1.3 mm vs 6.9 +/- 2.1 mm; P = ns). Cross-sectional images of the pulmonary artery wall demonstrated a single ring with high echodensity with a thin inner layer regarded as intima in group 1. In contrast, the majority of patients (n = 35/39) in group 2 demonstrated a thickening of the intimal layer and/or a disturbance of layering of the echogenic arterial wall. The relative wall thickness was higher in group 2 than in group 1 (22.5 +/- 10.4% vs 15.3 +/- 6.5%; P < 0.05). There were no significant correlations between pulmonary artery pressure and wall thickness pulmonary artery pressure and area change in the cardiac cycle, acetylcholine-dependent increase in pulmonary flow and morphological changes in the vessel wall.

CONCLUSION

We conclude that intravascular ultrasound is capable of detecting morphological changes in the pulmonary vessel wall in pulmonary hypertension and that vessel wall hypertrophy of small pulmonary segment arteries, as detected by intravascular ultrasound, is not predictive of functional vasodilatory response of resistance vessels of the same vessel area.

Acetylcholine causes dose dependent increase in pulmonary flow in patients with chronic heart failure and elevated pulmonary vascular resistance

Elevated pulmonary vascular resistances occur to a variable degree in patients with chronic congestive heart failure (CHF). These might be caused by increased levels of endogenous vasoconstrictors, defective endothelial vasodilatory mechanisms or structural vascular abnormalities. To determine the contribution of defective endothelial mediated vasodilation, we tested 10 patients with CHF due to coronary artery disease (n = 4) or dilated cardiomyopathy (n = 5), and congenital corrected transposition of the great arteries (n = 1) (median pulmonary artery pressure 36 mmHg, range of pulmonary vascular resistance 0.94-10.7 WE). Patients were in median functional class NYHA III, median left ventricular ejection fraction was 21%, median oxygen uptake at the anaerobic threshhold was 8.25 ml/kg/min. Flow was measured by a flow wire (0.018 inch) positioned in a pulmonary artery branch with a diameter of 3-8 mm determined by intravascular ultrasound before. Acetylcholine infusion was adjusted to 10(-6), 10(-5) and 10(-4) molar concentrations in the pulmonary artery branch. A dose dependent increase in flow between 64 to 140% was seen in 8 out of 10 patients. We conclude: Acetylcholine mediated vasodilation is found in patients with CHF and elevated pulmonary vascular resistances.

Current guidelines for the treatment of congestive heart failure

Overt congestive heart failure (CHF) has a prevalence of 1% of the population. The predominant symptoms of patients with CHF are fatigue and dyspnoea. Fatigue is thought to result from changes in peripheral muscle metabolism secondary to decrease vasodilative capacity and physical inactivity. An increase of peripheral perfusion by vasodilator therapy and physical activity are therefore recommended. Beside overt decompensation, where dyspnoea results from acute pulmonary congestion due to backward failure, increased physiological dead space ventilation caused by pulmonary ventilation/perfusion mismatch accounts, to a large degree, for dyspnoea, and can be improved by vasodilator therapy. According to the pathophysiology of CHF, normalisation of loading conditions and myocardial inotropy are the parameters addressed by various pharmacological agents in order to alleviate symptoms and slow progression of the disease. Diuretics are rapidly acting and effective agents to improve congestion and decrease filling pressures. Digitalis improves haemodynamics and symptomatology by increasing inotropy and slowing resting heart rate in atrial fibrillation; however, prognostic effects have yet to be proved. The introduction of vasodilators has significantly improved the prognosis of the disease, and the administration of ACE inhibitors in particular has been shown to slow progression of CHF. This results in a substantial decrease in morbidity and mortality. The present article appraises the role of the currently used drugs in the treatment of CHF, considering effects on pathophysiology and clinical outcome and provides an approach to a differential drug regimen.

Assessing appropriateness of treatment: a case study of transplantation in older patients with congestive heart failure

OBJECTIVE

To evaluate the appropriateness of transplantation therapy for older patients with congestive heart failure (CHF).

DATA SOURCES

Comparative review of contemporary survival and quality of life data of CHF patients treated medically versus by transplantation.

DATA SYNTHESIS

Approximately 300,000 Canadians have CHF and the incidence is increasing as the population ages; suitable donor allografts are found for about 300 CHF patients each year. Overall survival among cardiac allograft recipients, with a mean age of 48 years, is approximately 80% at two years. However, risk from all causes appears higher, and survival lower (range 40 to 78%), for transplant patients 55 years of age and older. Among medically treated patients, with mean age over 60 years, survival is inversely related to level of functional disability, averaging more than 90% at two years for patients with mild limitation and decreasing to 75% and 40% for patients with moderate and severe symptoms, respectively. Perceived quality of life is low in all CHF patients, but is significantly improved by intense out-patient care and education, irrespective of medical or transplant allocation.

CONCLUSIONS

Among adults with CHF, the greatest benefit of transplantation is enhanced survival in younger severely disabled patients. However, noncardiac risks are substantial, particularly for older recipients. The great discrepancy between donor and candidate availability prohibits transplantation from being a life expanding therapy for the whole CHF population. When physicians are, simultaneously, patients' and society's advocates a utilitarian decision model using the totality of efficacy data, including degree of efficacy and population effectiveness, may assist determination of the most appropriate therapy.

Can practice patterns and outcomes be successfully altered? Examples from cardiovascular medicine. The Clinical Quality Improvement Network (CQIN) Investigators

OBJECTIVE

To offer an attributive opinion of recent improvements in acute myocardial infarction (AMI) practice patterns and patient outcomes in the culture of an active health care research program.

DATA SOURCES

Review of original clinical data from five sequential, consecutively enrolled, AMI patient cohorts at the University of Alberta Hospitals from 1987-93.

DATA SYNTHESIS

Early cohorts had low use of trial-proven efficacious therapies for AMI, particularly among high risk older and female patients. Over time, there were continuous and marked increases in the use of efficacious therapies and decreased use of nonefficacious therapies, with a parallel decrease in mortality among high risk patients.

CONCLUSIONS

In a large tertiary care hospital between 1987 and 1993 the use of evidence-based AMI therapy and survival in high risk patients significantly increased. The continuity and large size of these improvements in AMI practice patterns, compared with similar populations reported in the contemporary literature, suggest it is unlikely they were due to chance. Rather, intercurrent repeated measurement and reporting of key health care performance indicators, and initiation of explicit critical path AMI practice guidelines provide a more likely explanation. Future studies by a network of community and university investigators will test whether these findings are true for a broad AMI population and whether similar practice definition and improvement tools are effective for other cardiac problems, including the management of congestive heart failure.

Cost reduction in cardiac surgery

OBJECTIVE

To reduce surgical waiting lists at the University of Alberta Hospitals. A cost reduction program was initiated, allowing more cases to be performed on the same budget. Reducing the cost of delivering health care services has become necessary as demands upon the system increase.

METHODS

Data were retrospectively gathered on patients having open heart surgery at the University of Alberta Hospitals between March 1, 1991 and February 29, 1992. Group 1 were patients operated on before the start of the cost reduction program (September 1, 1991) and group 2 were those operated on after. Student's t test and logistic regression were use to compare population characteristics and to correlate dependent variables.

RESULTS

Demographic features and severity indices were not different. Operating time decreased from 4.5 +/- 1.5 to 4 +/- 1 h, P < 0.002. Preoperative, intensive care unit (ICU) and postoperative ward length of stay were reduced (P < 0.002). Total length of stay went from 19.3 +/- 22.7 to 13.8 +/- 10.7 days, P < 0.001. Operating room, nursing and x-ray costs decreased, P < 0.002. Hospital costs declined from $14,182 +/- 16,464 to $10,710 +/- 7,332, P < 0.001. Multiple regression showed hospital stay, ICU, operating room time, severity of illness and age to be significant determinants of cost, P < 0.03 for each. Waiting time and number of patients on the waiting list declined significantly as surgical lists increased. Mortality and rate of readmission following discharge were not different between the two groups.

CONCLUSIONS

Substantial cost savings can be made by changing practice patterns, without adverse consequences. ICU and hospital length of stay are the most important cost determinants.

Acute hemorrhagic pancreatitis and diabetes mellitus following endoscopic retrograde cholangiopancreatography

Endoscopic retrograde cholangiopancreatography (ERCP) is generally regarded as a safe and useful investigation in the diagnosis and management of diseases of the pancreas and biliary tree. Asymptomatic hyperamylasemia is not uncommon following this procedure, but clinical pancreatitis is rare. The authors report on a 56-year-old man who suffered life-threatening acute hemorrhagic pancreatitis 2 weeks after ERCP was performed for the investigation of abdominal pain. He subsequently had insulin-dependent diabetes mellitus, which was not present at the time of ERCP.

Ranitidine in the treatment of symptomatic gastroesophageal reflux disease

We undertook a multicenter double-blind study comparing ranitidine to placebo in 73 patients with symptomatic gastroesophageal reflux ranging in age from 22 to 80 years (mean 49). Initially, all patients had moderate to severe symptoms associated with abnormal endoscopic and/or microscopic appearance of the mucosa. After six weeks, 46% of ranitidine-treated patients had a one-grade improvement in their symptom of regurgitation, as compared with 19% treated with placebo (p less than 0.01); ranitidine was no better than placebo in the improvement of pain or dysphagia. Endoscopic improvement occurred in 61% of ranitidine- and 48% of placebo-treated patients (p less than 0.05). Histological improvement occurred in a similar and small portion of patients treated with ranitidine and placebo; there was no correlation between clinical, endoscopic, and histological improvement. Antacid consumption was only half as great in the ranitidine as in the placebo group. Therapy with ranitidine was maintained for up to 12 months. The patients remained free of regurgitation or pain and there was a trend towards further improvement in the endoscopic or histopathologic appearance of the esophagus. Ranitidine 150 mg b.i.d. is recommended for the relief of symptoms and improvement in the endoscopic appearance of the esophagus. Treatment should be for a minimum of 6 weeks, but may be continued for up to a year if the patient's symptoms persist or return.

Gastrin, gastric emptying, and gastroesophageal reflux after ranitidine

In a double-blind study comparing ranitidine to placebo in the treatment of symptomatic gastroesophageal reflux disease (GERD), we assessed gastric emptying time, gastroesophageal reflux, and gastrin response to food. Mean half-time for gastric emptying, measured using 99mTc-sulfur colloid, was 109 minutes in GERD and 102 minutes in nine healthy asymptomatic controls. This difference was not significant, but one-third of GERD had emptying times of 2 S.D.s beyond the mean for the normal controls. The patients with GERD refluxed an average of 2.3% (0.1-10%) of the isotope in 120 minutes compared with only 0.2% (0.0-0.5%) in control subjects. Reflux scans and gastric emptying times did not change with healing of esophagitis or with symptomatic improvement from ranitidine and antacids. There was no relationship between the percentage of the test dose refluxed into the esophagus and the rate of gastric emptying. The mean fasting gastrin concentration in GERD, 133 +/- 12 pg/ml, was higher than in healthy controls, 93 +/- 10 pg/ml (p less than 0.01). After stimulation with a standard meal, the integrated gastrin response (IGR) was similar in controls and GERD patients, but IGR was significantly higher after 6 weeks therapy with ranitidine. These results suggest that: 1) gastric emptying time may be prolonged in some patients with GERD, 2) basal but not food-stimulated gastrin concentrations may be abnormal in GERD, 3) reflux scans have limited use in the investigation of GERD, and 4) ranitidine therapy is associated with an increase in food-stimulated gastrin concentrations.

Cimetidine for recurrent ulcer after gastric surgery

Seven of nine patients with ulcers recurring after a variety of gastric operations enjoyed loss of dyspeptic symptoms within 2 days of taking cimetidine, 1,200 mg/day for 6 weeks, and endoscopic confirmation of healing of the recurrent ulcer was established within 6 weeks of therapy. Once ulcer healing had been achieved in these seven patients, symptomatic remission persisted for over 19 months without maintenance therapy with cimetidine, and no complications suggestive of recurrent ulcerations occurred during this period in these seven patients. The eighth patient with a recurrent ulcer after vagotomy and pyloroplasty had symptoms suggestive of a gastric outlet obstruction in association with a bezoar and an elevated fasting serum gastrin concentration; cimetidine failed to heal the ulcer and a partial gastrectomy with Billroth I anastomosis was undertaken. The ninth patient lost his dyspeptic symptoms while on cimetidine, but 1 month after stopping therapy he succumbed to a massive hemorrhage; autopsy revealed a large pyloric channel ulcer. We suggest that cimetidine is helpful for the control of symptoms and the healing of recurrent ulcers after gastric surgery, but that endoscopy be repeated after an appropriate interval while such patients remain on cimetidine to assure that the disappearance of symptoms is truly associated with a lack of peptic ulceration. If the ulceration persists, we believe that cimetidine should be continued for a longer period.