Coronary tortuosity in patients with acetylcholine-induced coronary microvascular spasm

Background

Angina pectoris in the absence of relevant epicardial stenoses (ANOCA) is frequently caused by coronary microvascular spasm. It has been speculated that the morphology of epicardial coronary arteries is associated with microvascular spasm. One hypothesis is that the vasoconstriction of microvessels leads to intraluminal pressure increase in the vascular segments proximal to the spasm, which may shift the balance of vessel forces toward vessel elongation resulting in coronary tortuosity.

Purpose

We assessed the relationship between epicardial coronary tortuosity and coronary spasm to elucidate a potential relationship between structural and functional coronary abnormalities.

Methods

610 patients (39% male, mean age 61 years) with stable angina yet unobstructed coronary arteries (<50% stenosis) were included in this study. All patients underwent invasive diagnostic coronary angiography followed by intracoronary acetylcholine (ACh) testing according to a standardized protocol. The ACh test was considered “positive” in the presence of (a) angina, ischemic ECG shifts during the test and ≥90% coronary diameter reduction (“epicardial spasm”) or (b) all above without epicardial spasm (“microvascular spasm”). Assessment of coronary tortuosity was performed using left and right coronary images in multiple projections in a blinded fashion. The number and angles of the coronary curves in late diastole determined the severity of coronary tortuosity previously defined by Eleid. Patients were divided into those with at least moderate tortuosity versus those with no or mild tortuosity.

Results

ACh-testing revealed epicardial spasm in 179 (29%) and microvascular spasm in 172 (28%) patients. The ACh-test was negative/inconclusive in the remaining 259 patients (43%). There were 298 patients (49%) with at least moderate coronary tortuosity. The remaining 312 patients had no or mild coronary tortuosity (51%). Patients with at least moderate tortuosity were more likely to have microvascular spasm (99 patients of 172 with microvascular spasm had at least moderate coronary tortuosity (58%) vs. 76 patients of 179 with epicardial spasm (43%) vs. 126 patients of 259 with negative/inconclusive ACh test (49%), p=0.017). Analysis of coronary tortuosity in patients with positive ACh-test showed that patients with at least moderate coronary tortuosity (n=175) had significantly more microvascular spasm (57%) than epicardial spasm (43%) (p=0.005). We also found that at least moderate coronary tortuosity was significantly more often found in patients with hypertension compared to patients without hypertension (230/438 vs. 71/172, p=0.015).

Conclusions

In this large cohort of ANOCA patients coronary tortuosity was associated with hypertension and microvascular spasm. Our results provide interesting insights into the relationship of coronary morphology and vasomotor function.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Berthold-Leibinger-Foundation, Ditzingen, Germany

Prognostic impact of plasma level of NT-pro BNP in patients with microvascular angina – a report from the international cohort study by COVADIS

Aims

Although the importance of microvascular angina (MVA) has been emerging, prognostic biomarkers for MVA remain to be developed. We thus aimed to examine whether plasma level of N-terminal prohormone of brain natriuretic peptide (NT-pro BNP) could predict the prognosis of MVA patients.

Methods

In the international prospective cohort study of MVA patients by the Coronary Vasomotor Disorders International Study (COVADIS) group, we evaluated the association between plasma level of NT-pro BNP and the incidence of major adverse cardiovascular events (MACE), including cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, and hospitalization due to heart failure or unstable angina.

Results

We examined a total of 226 MVA patients (M/F 66/160, 61.9±10.2 [SD] years) with both plasma NT-pro BNP levels and echocardiographic data in the COVADIS study. Plasma NT-pro BNP level was elevated (median 94 pg/ml, IQR 45–190) while mean LVEF (69.2±10.9%) and E/e' (10.7±5.2) were almost normal. During follow-up period of a median of 365 days (IQR 365–482), 29 MACEs occurred. ROC curve analysis identified plasma NT-pro BNP level of 78 pg/ml as the optimal cut-off value. Multivariable logistic regression analysis revealed that plasma NT-pro BNP level ≥78 pg/ml significantly correlated with the incidence of MACE (odds ratio (OR) [95% confidence interval (CI)] 3.11 [1.14–8.49], P=0.03). When divided into 2 groups by NT-pro BNP 78 pg/ml, the Kaplan-Meier survival analysis showed a significantly worse prognosis in the group with NT-pro BNP ≥78 (log lank, P=0.03) (Figure).

Conclusions

These results indicate that plasma NT-pro BNP level is a novel prognostic biomarker for MVA patients.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Japan Heart Foundation

Coronary computed tomographic angiography as gatekeeper for new-onset stable angina

Patients with new-onset stable angina constitute a substantial part of the population seen by cardiologists. Currently, the diagnostic workup of these patients depends on the pre-test probability of having obstructive coronary artery disease. It consists of either functional testing for myocardial ischaemia or anatomical testing by using coronary computed tomographic angiography (CCTA) or invasive coronary angiography. In case the pre-test probability is > 5%, the current guidelines for the management of chronic coronary syndromes do not state a clear preference for one of the noninvasive techniques. However, based on the recently published cost-effectiveness analysis of the PROMISE trial and considering the diagnostic yield in patients with angina and nonobstructive coronary artery disease, we argue a more prominent role for CCTA as a gatekeeper for patients with new-onset stable angina.

Long-term follow-up of patients with MINOCA (myocardial infarction with unobstructed coronary arteries) undergoing intracoronary spasm provocation testing

Background

Up to 30% of patients presenting with acute coronary syndrome undergoing coronary angiography are found to have no culprit lesion. Among them, epicardial or microvascular spasm can be diagnosed in ∼50% of patients undergoing provocative testing. While prognostic data in patients with coronary spasm and stable angina are abundant, the outcome of patients with myocardial infarction and unobstructed coronaries (MINOCA) and coronary spasm is not clear.

Purpose

The aim of this study was to investigate the prognosis of a cohort of patients presenting with MINOCA undergoing intracoronary acetylcholine (ACH) spasm testing.

Methods

We evaluated consecutive patients with MINOCA undergoing acetylcholine testing to detect epicardial or microvascular spasm from 2014 to 2017. Other aetiologies for MINOCA such as myocarditis, supraventricular tachycardia, pulmonary embolism etc. were excluded. Data regarding mortality (cardiac/non-cardiac), nonfatal myocardial infarction (MI), repeated coronary angiography and percutaneous coronary intervention (PCI) were recorded.

Results

Of 112 patients in our study, follow-up data were available for 96 patients (86%, 51% women, mean age 63±13 years). Acetylcholine testing was positive in 51 (53%) patients. Among patients with a positive test, epicardial spasm was detected in 26 (51%) and microvascular spasm in 25 (49%) patients. After a median follow-up of 5±3.5 years, 7 deaths (7%) and 20 nonfatal myocardial infarctions (21%) occurred. Moreover, 19 patients (20%) underwent coronary angiography and 9 patients (9%) received a PCI. Comparisons of the Kaplan–Meier curves by log-rank test showed that patients with positive acetylcholine test had a worse outcome compared to those with a negative test in terms of death from any cause (p=0.01), myocardial infarction (p=0.03) and repeated coronary angiography (p=0.05).

Conclusion

This follow-up study shows that prognosis of MINOCA patients with coronary spasm on provocative testing is worse compared to patients with an uneventful test. The results underline the potential prognostic value of spasm testing in MINOCA patients.

Funding Acknowledgement

Type of funding sources: None.

Reference values for intracoronary doppler flow velocity-derived hyperaemic microvascular resistance index

Background

Invasive assessments of microvascular function are rapidly becoming an integral part of physiological assessment in chronic coronary syndromes.

Objective

We aimed to establish a reference range for Doppler flow velocity-derived hyperaemic microvascular resistance index in a cohort of ANOCA patients with no structural pathophysiological alterations in the coronary circulation.

Methods

The reference population consisted of ANOCA patients undergoing invasive coronary vasomotor function assessment who had a coronary flow reserve (CFR) >2.5, and had either (1) tested negatively for spasm provocation (n=12) or (2) tested positively with only angina at rest (n=29). A reference range for HMR was established using a non-parametric method and correlations with clinical characteristics were determined using a spearman rank correlation analysis.

Results

In 41 patients median HMR amounted to 1.6 mmHg/cm/s [Q1, Q3: 1.3, 2.2 mmHg/cm/s]. The reference range for HMR that is applicable to 95% of the population was 0.8 mmHg/cm/s (90% CI: 0.8–1.0 mmHg/cm/s) to 2.7 mmHg/cm/s (90% CI: 2.6–2.7 mmHg/cm/s). No significant correlations were found between HMR and clinical characteristics.

Conclusion

In this reference population undergoing invasive coronary vasomotor function testing, the 90% confidence interval of the HMR upper limit of normal ranges from 2.6 to 2.7 mmHg/cm/s. A >2.5 mmHg/cm/s HMR threshold can be used to identify abnormal microvascular resistance in daily clinical practice.

Funding Acknowledgement

Type of funding sources: None. Example of HMR measurement

Proteomic biomarker profiles and vascular dysfunction in angina with no obstructive coronary artery disease

Background

Coronary vascular dysfunction is a common cause of symptoms in patients with angina and no obstructed coronary arteries (ANOCA). Several endotypes have been defined but there are big gaps in our understanding of the underlying pathophysiology. Proteomic analyses may improve the understanding of the pathophysiology.

Purpose

Exploratory approach to 1) compare the proteomic biomarker profile across different types of vascular dysfunction in ANOCA and 2) assess the value of prediction models with protein biomarkers for vascular dysfunction in ANOCA.

Methods

We included 107 angina patients without previous coronary artery disease, left ventricular ejection fraction >45% and no obstructive coronary artery disease (CAD) (<50% stenosis of epicardial vessels) on coronary angiography. Three types of vascular dysfunction were assessed: 1) Vasomotor dysfunction (VMD) defined as epicardial or microvascular vasospasm on acetylcholine provocation, 2) Coronary microvascular dysfunction (CMD) defined as coronary flow velocity reserve (CFVR) ≤2.5 on echocardiography of the LAD on adenosine stimulation and 3) Reactive Hyperaemia Index (RHI) ≤1.67 as a measure of peripheral endothelial dysfunction. Blood samples were analysed for 184 protein biomarkers related to cardiovascular disease. Correlations between biomarkers and results of vascular function assessments were analysed with Pearson's correlation coefficient and visualized with volcano plots. Significantly correlated biomarkers (p<0.05) were tested in prediction models for their incremental value over age and gender with C-statistics.

Results

CFVR was correlated to 24 biomarkers before (figure 1a) and 2 biomarkers after adjustment for age and gender. The basic prediction model had AUC of 0.68 and was not significantly improved by adding biomarkers (figure 2a). RHI was correlated to 27 biomarkers before (figure 1b) and 10 biomarkers after adjustment for age and gender. The clinical prediction model was significantly improved (p=0.037) by adding TRAIL R2 and IL-18, in addition to age and gender, with an AUC of 84.4 (figure 2b). VMD was correlated to 14 biomarkers before (figure 1c) and 6 biomarkers after adjustment for age and gender. The prediction model was significantly improved (p=0.011) by adding HSP-27, RARRES-2 and SERPINA-12 in addition to age and gender in prediction of VMD with an AUC of 85.4 (figure 2c).

Conclusion

Several biomarkers were associated with vascular dysfunction in ANOCA patients with little overlap between different endotypes. We identified biomarkers that may contribute to the understanding of the underlying pathophysiology and have applications for screening. Results need to be confirmed in larger studies.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Department of Cardiology, Bispebjerg and Frederiksberg Hospital, University of Copenhagen, Denmark.Department of Cardiology and Angiology, Robert Bosch Krankenhaus, Stuttgart, Germany

Mechanisms of angina in patients with biopsy-proven viral myocarditis: insights from intracoronary acetylcholine testing

Background

Patients with myocarditis often present with angina pectoris despite unobstructed coronary arteries. The underlying pathophysiological mechanism of angina in these patients remains to be elucidated. Coronary artery spasm is a well-known cause of angina in patients with unobstructed coronary arteries. In this study, we sought to assess the frequency of coronary vasomotor disorders in patients with biopsy-proven viral myocarditis.

Methods

In total, 700 consecutive patients who underwent endomyocardial biopsy for suspected myocarditis between 2008 and 2018 were retrospectively screened. Of these patients, viral myocarditis was confirmed in 303 patients defined as histological/immunohistological evidence of myocardial inflammation and presence of viral genome confirmed by PCR. Of these patients, 34 patients had angina despite unobstructed coronary arteries and underwent intracoronary acetylcholine (ACh) provocation testing in search of coronary spasm. Epicardial spasm was defined as acetylcholine-induced reproduction of the patient's symptoms associated with ischemic ECG changes and >90% epicardial vasoconstriction. Microvascular spasm was defined as symptom reproduction and ECG changes in the absence of significant epicardial vasoconstriction.

Results

Patients were 49±16 years old, 62% were male and left ventricular ejection fraction was 54±16%. Most frequent viruses were parvovirus B19 (PVB19, 59%) and human herpes virus 6 (HHV6, 26%), 2 patients had combined PVB19/HHV6 infection and 3 patients other herpesviruses (CMV, EBV, VZV). Epicardial spasm was observed in 10 patients (29%) during ACh testing and microvascular spasm was found in 11 patients (32%). The rate of coronary spasm (epicardial and microvascular) was higher in the PVB19 subgroup compared to HHV6 (80% vs. 33%, p=0.031). In particular, there was a higher prevalence of microvascular spasm in PVB19 compared to HHV6 (45% vs. 0%, p=0.018).

Conclusion

We observed a high prevalence of microvascular and epicardial spasm in patients with biopsy-proven viral myocarditis suggesting coronary spasm as a potential underlying mechanism for angina in these patients. Microvascular spasm was most often observed in patients with PVB19-associated myocarditis.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Robert-Bosch-Stiftung; Berthold-Leibinger-Stiftung

Intracoronary acetylcholine spasm testing: differences in epicardial coronary artery response between smooth and atherosclerotic coronary arteries

Background

Coronary artery spasm is an established cause for angina pectoris. Epicardial coronary spasm may occur in patients with obstructed as well as unobstructed coronary arteries. Previous studies have suggested that epicardial plaque/atherosclerosis is a prerequisite for the development of epicardial spasm. The aim of the present study was to compare the results of intracoronary acetylcholine (ACh) testing in patients with signs and symptoms of myocardial ischemia with completely smooth versus atherosclerotic yet unobstructed epicardial arteries.

Methods

Between 2008 and 2016 a total number of 617 patients with signs and symptoms of myocardial ischemia yet unobstructed epicardial arteries (<50% epicardial stenosis) was included in the present study (mean age 61±11, 61% female). All patients underwent invasive diagnostic coronary angiography followed by intracoronary ACh testing according to a standardized protocol. The ACh-test was considered “positive” in the presence of (a) angina, ischemic ECG shifts during the test and ≥75% focal or diffuse coronary diameter reduction (“epicardial coronary artery spasm”) or (b) ischemic ST-shifts and angina in the absence of epicardial spasm (“microvascular spasm”). All angiograms were assessed regarding any visible epicardial plaque/atherosclerosis in a blinded fashion and patients were categorized into those with completely smooth versus those with atherosclerotic coronary arteries. The analysis included 179 patients (29%) with epicardial spasm and 172 patients with microvascular spasm (28%). The remaining 266 patients (43%) had an uneventful or an inconclusive ACh-test result.

Results

There were 389 patients (63%) with completely smooth epicardial arteries. The remaining 228 patients (37%) had non-obstructive epicardial plaques <50%. Patients with smooth arteries developed epicardial spasm in 24%, microvascular spasm in 32% and a negative/inconclusive test result in 44% of cases. Patients with atherosclerotic arteries developed epicardial spasm in 38%, microvascular spasm in 21% and an inconclusive/negative test result in 41% of cases. On univariate analysis the presence of epicardial atherosclerosis was associated with epicardial spasm (p=0.006) whereas this was not the case for microvascular spasm (p=0.094). Multivariate analysis revealed the presence of epicardial atherosclerosis (OR 1.921, CI 1.285–2.871, p=0.001) as well as female sex (OR 1.526, CI 1.024–2.274, p=0.038) as independent predictors for epicardial spasm.

Conclusion

In patients with signs and symptoms of myocardial ischemia yet unobstructed coronary arteries the presence of epicardial atherosclerosis is an independent predictor for the occurrence of epicardial spasm but not microvascular spasm on acetylcholine testing.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Robert-Bosch-Stiftung, Berthold-Leibinger-Stiftung

P875Myocardial perfusion reserve assessment in patients with angina pectoris and suspected coronary spasm

Background

Patients with signs and symptoms of myocardial ischemia yet unobstructed coronary arteries represent a diagnostic and therapeutic challenge. Coronary vasomotor disorders such as coronary epicardial or microvascular spasm are frequently found among these patients. They can be diagnosed using intracoronary acetylcholine testing (ACH-test). It has been shown that patients with epicardial spasm have a worse prognosis compared to patients with microvascular spasm. The reasons for this finding are however not apparent. We speculated in this study that patients with epicardial spasm have a worse vasomotor dysfunction compared to patients with microvascular spasm or normal ACH-test. To assess this hypothesis all patients in this study not only underwent ACH-testing but in addition also adenosine stress perfusion cardiac MRI (CMR) with calculation of the myocardial perfusion reserve index (MPRI). The latter method allows for assessment of vasodilatory function compared to the vasoconstrictor assessment using acetylcholine.

Methods

Between 2012 and 2016, 129 consecutive patients (mean age 64±13 years, 46% female) with signs and symptoms of myocardial ischemia yet unobstructed coronary arteries were enrolled in this study. All patients underwent ACH-testing as well as adenosine stress perfusion CMR. According to the results of the acetylcholine test, patients were allocated to 3 groups: a) epicardial spasm (angina, ischemic ECG changes and >75% coronary diameter reduction), b) microvascular spasm (angina, ischemic ECG changes and <75% coronary diameter reduction) and c) no evidence of coronary artery spasm. CMR-derived MPRI was calculated semiquantitatively from myocardial signal intensity-over-time curves of adenosine stress and rest perfusion.

Results

Epicardial and microvascular spasm was found in 31 (24%) and 69 (53%) patients, respectively, while 29 (22%) patients had no evidence of coronary spasm on ACH-testing. Women were more likely to have microvascular spasm than men (68% vs. 36%, p<0.001). The prevalence of epicardial spasm did not significantly differ between female and male patients (18% vs. 31%, p=0.08). MPRI was similar in patients with microvascular spasm compared to patients without spasm (1.30 vs. 1.27, p=0.43). However, patients with epicardial spasm had significantly lower MPRI than patients without spasm (1.16 vs. 1.30, p<0.05) or those with microvascular spasm (1.16 vs. 1.27, p<0.05).

Conclusion

MPRI determined by stress perfusion CMR was significantly reduced in patients with epicardial spasm compared to those with microvascular spasm or normal ACH-test. This could indicate that patients with epicardial spasm have a more generalized coronary vasomotor disorder compared to other patients. This may be the reason for the worse outcome observed and could lead to more aggressive medical therapy and closer follow-up.

Acknowledgement/Funding

This work was funded by the Robert-Bosch-Stiftung, Stuttgart, Germany and the Berthold-Leibinger-Stiftung, Ditzingen, Germany.

[Effect of humor training on stress, cheerfulness and depression in patients with coronary artery disease and refractory angina pectoris]

BACKGROUND

Angina pectoris refractory to conventional medical treatment is a common phenomenon in patients with stable coronary artery disease (CAD). Many of these patients suffer from depression and generate substantial costs in the healthcare system. Therefore, the development of new therapeutic concepts is of particular importance. This study investigated whether professional, structured humor training has a positive effect on the symptoms of patients with treatment refractory angina pectoris.

METHODS

Between 2013 and 2014 a total of 35 patients with stable CAD were included. Enrolment was possible if patients suffered from treatment refractory angina pectoris (Canadian Cardiovascular Society, CCS grades II-IV) despite optimal antianginal medication and exhaustion of options for myocardial revascularization. Previously, 25.8% of the patients had had a myocardial infarction. In this study, a professional humor coaching was conducted with a duration of 7 weeks. In order to evaluate the effects of the coaching, the following examinations were performed before and after the intervention: exercise stress test (treadmill), hair segment cortisol analysis, Beck Depression Inventory (BDI), the Trier Inventory for the Assessment of Chronic Stress (TICS) and the State-Trait-Cheerfulness Inventory (STCI).

RESULTS

Out of the 35 initially recruited patients 31 completed the study. The mean age was 65.5 years and 94.5% were female. There was a significant improvement in cheerfulness (STCI, pre 23.3 ± 5.4, post 27.5 ± 5, p = 0,03). This effect was even stronger in a subgroup analysis in which only female patients were included (pre 23.6 ± 5.5, post 27.7 ± 4.6, p = 0.003). The results of the BDI showed a remarkable improvement in the pre-post analysis (pre 14.6 ± 8.1, post 11.0 ± 6.5, p = 0.064). Analyzing only the female patients, this difference became significant (pre 13.1 ± 6.4, post 9.9 ± 4.6 p = 0,037). The hair segment investigations showed that patients who had a higher cortisol level in the beginning (>25. percentile, n = 22) showed a significant reduction of the cortisol concentration (pre 6.54 pg/mg, 3.78-12.12 pg/mg, post 3.65 pg/mg, 2.82-7.68 pg/mg, p = 0.029).

CONCLUSION

Patients with refractory angina pectoris and stable CAD benefit from a professional humor coaching. This effect was shown in a) a significant decrease in cortisol concentrations in the hair segment analysis, b) an improvement in cheerfulness in the STCI and c) a significant difference in the BDI between pre-post values.

[Recommendations of the ESC guidelines regarding cardiovascular imaging]

Cardiac imaging plays a key role in the diagnosis and risk stratification in the ESC guidelines for the management of patients with stable coronary artery disease. Demonstration of myocardial ischaemia guides the decision which further diagnostic and therapeutic strategy should be followed in these patients. One should, however, not forget that there are no randomised studies supporting this type of management. In patients with a low pretest probability coronary CT angiography is the optimal tool to exclude coronary artery stenoses rapidly and effectively. In the near future, however, better data is needed showing how much cardiac imaging is really necessary and how cost-effective it is in patients with stable coronary artery disease.

The inflammatory response between miniaturised and conventional cardiopulmonary bypass after cardiac surgery in an Asian population

INTRODUCTION

We compared the systemic inflammatory response of the MCPB system to the CCPB system with cell salvage and phosphorylcholine-coated tubing amongst Asian patients undergoing coronary artery bypass grafting.

METHODS

Seventy-eight patients were randomly assigned to the MCPB or the CCPB groups equally and followed up in a prospective, single-blinded, randomised, controlled trial. Levels of TNF-α, IL-6, CRP and LDH were measured peri-operatively.

RESULTS

The systemic inflammatory response was similar in both groups (TNF-α: p=0.222; IL-6: p=0.991; CRP: p=0.258). Only haemolysis was significantly higher in the CCPB group (LDH: p=0.011). The MCPB system was twice more expensive, but had a near 4-fold cost saving in tranfusions. Overall, the MCPB system cost 20% more than the modified CCPB system.

CONCLUSION

These results corroborate with studies that demonstrated the avoidance of cardiotomy suction rather than the MCPB system, itself, leads to an attenuated inflammatory response. The absence of obvious clinical benefit and the higher costs involved with the MCPB system would preclude its routine use.

[Unstable angina pectoris--combination of an epicardial stenosis and a Prinzmetal spasm]

HISTORY AND ADMISSION FINDINGS

A 61-year-old man presented with recurrent angina pectoris at rest for 3 days. The medical history revealed hypertension and an elevated cholesterol level as cardiovascular risk factors.

INVESTIGATIONS

The physical examination revealed no pathological findings. ECG at admission showed no signs of ischemia, while high-sensitive Troponin T was slightly elevated. Echocardiography showed diastolic dysfunction and biatrial dilatation.

TREATMENT AND COURSE

During another episode of angina at rest, ECG showed T-wave inversion in lead aVL. Therefore, coronary angiography was performed. At the beginning of the examination the patient complained of angina at rest and ECG showed ST-elevation in the inferior leads. Coronary angiography revealed a subtotal stenosis in the middle part of the RCA. After intracoronary nitroglycerin injection there was a high-grade stenosis in this region. An intracoronary acetycholin provocation test was performed which reproduced a focal spasm in the area of the RCA stenosis with simultaneous changes in the ECG and reproduction of the patient's unusual angina. After implantation of a bare metal stent a subsequent ACH-test did not elicit any further coronary spasm. Four weeks after the procedure the patient had no further complaints under medical treatment.

CONCLUSION

This case illustrates a patient with a focal Prinzmetal-type spasm with ST-elevation on top of a high-grade stenosis of the right coronary artery as an explanation for the unstable angina. Coronary spasm of the Prinzmetal-type can occur in vessels with epicardial stenosis as well as in vessels without stenosis. In some cases focal coronary spasm can be prevented by the implantation of a stent.

Multispecies coexistence of trees in tropical forests: spatial signals of topographic niche differentiation increase with environmental heterogeneity

Neutral and niche theories give contrasting explanations for the maintenance of tropical tree species diversity. Both have some empirical support, but methods to disentangle their effects have not yet been developed. We applied a statistical measure of spatial structure to data from 14 large tropical forest plots to test a prediction of niche theory that is incompatible with neutral theory: that species in heterogeneous environments should separate out in space according to their niche preferences. We chose plots across a range of topographic heterogeneity, and tested whether pairwise spatial associations among species were more variable in more heterogeneous sites. We found strong support for this prediction, based on a strong positive relationship between variance in the spatial structure of species pairs and topographic heterogeneity across sites. We interpret this pattern as evidence of pervasive niche differentiation, which increases in importance with increasing environmental heterogeneity.

Depression: reduced number of granule cells in the hippocampus of female, but not male, rats due to prenatal restraint stress

It has been hypothesized that decreased neurogenesis in the dentate gyrus may be involved in mediating depressive disorders, which are 1.5-3 times more frequent in women than in men. Additionally, prenatal stress may increase the risk of developing depression in adulthood. However, the interrelations between prenatal stress and the development of depression in adulthood, preferentially in females, are not understood. Here, we subjected pregnant rats to a single 20-min period of restraint stress on day 18 after mating. When the offspring were 75 days of age, the numbers of granule cells and pyramidal cells (area CA1-3) in the hippocampus were analyzed with the optical fractionator. The Cavalieri's principle was applied to analyze the volumes of both granule cell layer and pyramidal cell layer in the hippocampus. Prenatally stressed females, but not males, had reduced numbers of hippocampal granule cells compared to their non-prenatally stressed counterparts. This is the first report of a sex-specific difference concerning the reduction of the number of hippocampal granule cells due to prenatal stress. In humans, prenatal stress may induce cell loss in the granule cells of the hippocampus preferentially in females compared to males, and this may be a sex-specific predisposing factor for the development of depression in adulthood.

High-Resolution FTIR Spectrum of the nu(12) Band of trans-d(2)-Ethylene

The nu(12) band of trans-d(2)-ethylene (trans-C(2)H(2)D(2)) has been recorded with an unapodized resolution of 0.0024 cm(-1) in the frequency range of 1240-1360 cm(-1) by Fourier transform infrared (FTIR) spectroscopy. This band was found to be relatively free from any local frequency perturbations. By fitting a total of 1185 infrared transitions of nu(12) with a standard deviation of 0.00043 cm(-1) using a Watson's A-reduced Hamiltonian in the I(r) representation, a set of accurate rovibrational constants for v(12) = 1 state was derived. The nu(12) band is A type with a band center at 1298.03797 +/- 0.00004 cm(-1). Copyright 2000 Academic Press.

High-Resolution Fourier Transform Infrared Spectrum of the nu(12) Fundamental Band of Ethylene (C(2)H(4))

The infrared spectrum of the nu(12) fundamental band of ethylene (C(2)H(4)) has been measured with an unapodized resolution of 0.004 cm(-1) in the frequency range of 1380-1500 cm(-1) using the Fourier transform technique. By assigning and fitting a total of 1387 infrared transitions using a Watson's A-reduced Hamiltonian in the I(r) representation, rovibrational constants for the upper state (v(12) = 1) up to five quartic and three sextic centrifugal distortions terms were derived. They represent the most accurate constants for the band so far. The rms deviation of the fit was 0.00033 cm(-1). The A-type nu(12) band with a band center at 1442.44299 +/- 0.00003 cm(-1) was found to be relatively free from local frequency perturbations. The inertial defect Delta(12) was found to be 0.24201 +/- 0.00002 u Å(2). Copyright 2000 Academic Press.

Cytogenetic analysis of invasive breast cancer: a study of 27 Asian patients

Tumor cytogenetic analysis from 27 patients with breast cancer diagnosed at the Singapore General Hospital revealed complex karyotypic aberrations in 12 cases. The study group comprised 25 women and 2 men, ranging in age from 33 to 78 years (median 52 years). Ethnic distribution consisted of 22 Chinese, 3 Malaysian, and 2 Indian patients. Pathologic assessment disclosed 24 invasive ductal, 2 invasive mucinous, and 1 mixed invasive mucinous and ductal carcinomas. Histologic grading showed 3 grade 1, 10 grade 2, and 12 grade 3 tumors; 2 cancers were not graded, because they had been subjected to prior chemotherapy. Tumor sizes ranged from 1.5 to 10 cm (median 3 cm). Eleven cases were axillary node negative, whereas the remaining 16 node-positive cancers affected as many as 3 nodes in 8 cases and 4 or more nodes in another 8. Twenty cases demonstrated estrogen-receptor positivity, and 8 cases progesterone-receptor positivity. The spectrum of cytogenetic abnormalities involved chromosomes 1, 3, 6, 7, 8, 11, 16, and 17 and ranged from gains and deletions of both long and short arms, trisomy, monosomy, and other rearrangements. There was a trend toward the presence of karyotypic abnormalities in tumors of higher grade.

High-Resolution FTIR Spectrum of the nu(9) Band of Ethylene-D(4) (C(2)D(4))

The spectrum of the nu(9) fundamental band of ethylene-d(4) (C(2)D(4)) has been measured with an unapodized resolution of 0.004 cm(-1) in the frequency range of 2300-2400 cm(-1) using a Fourier transform infrared spectrometer. A total of 549 transitions have been assigned and fitted using a Watson's A-reduced Hamiltonian in the I(r) representation to derive rovibrational constants for the upper state (v(9) = 1) up to five quartic terms with a standard deviation of 0.00087 cm(-1). They represent the most accurate rovibrational constants for the nu(9) band so far. About 30 transitions of K(a)(') = 0, one transition of nu(9) which were identified to be perturbed possibly by the nearby nu(11) and nu(2) + nu(12) transitions, were not included in the final fit. The nu(9) band of C(2)D(4) was found to be basically B-type with an unperturbed band center at 2341.836 94 +/- 0.000 13 cm(-1). Copyright 2000 Academic Press.

Analysis of the Coriolis Interaction between nu(6) and nu(8) Bands of HCOOH

The Fourier transform infrared (FTIR) spectrum of the nu(6) band of formic acid (HCOOH) has been recorded with a resolution of 0.0024 cm(-1) in the spectral range 1050-1160 cm(-1). The nu(6) band was found to be strongly perturbed by the nearby nu(8) band centered at about 1033.5 cm(-1). Using a Watson's A-reduced Hamiltonian in the I(r) representation, and with the inclusion of a-type Coriolis coupling constant, a simultaneous fit of nu(6) and nu(8) was performed. A total of 2485 infrared transitions including about 700 perturbed transitions of nu(6) and 19 transitions of nu(8) was fitted with an rms uncertainty of 0.0006 cm(-1). Accurate rovibrational constants up to sextic order for both nu(6) and nu(8) were obtained. The nu(6) band was analyzed to be a type AB hybrid with a band center at 1104.852109 +/- 0.000050 cm(-1). The band center for nu(8) was found to be 1033.4647 +/- 0.0021 cm(-1). Copyright 2000 Academic Press.

The Coriolis Interaction between the nu(9) and nu(7) Fundamental Bands of Methylene Fluoride

The infrared spectrum of the nu(7) and nu(9) bands of methylene fluoride-d(2) (CD(2)F(2)) has been recorded with an unapodized resolution of 0.0024 cm(-1) in the frequency range of 940-1030 cm(-1) using the Fourier transform technique. A weak b-type Coriolis interaction term was found to couple these two vibrational states with band centers about 42 cm(-1) apart. By fitting a total of 1031 infrared transitions of both nu(7) and nu(9) with a standard deviation of 0.0011 cm(-1) using a Watson's A-reduced Hamiltonian in the I(r) representation with the inclusion of a b-type Coriolis resonance term, two sets of rovibrational constants for nu(7) = 1 and nu(9) = 1 states up to sextic order were derived. The nu(7) band is C type, while the nu(9) band is A type with band centers at 961.8958 +/- 0.0005 and 1003.7421 +/- 0.0001 cm(-1), respectively. Copyright 2000 Academic Press.

High resolution FTIR spectrum of the nu1 band of DCOOD

Accurate spectral information on formic acid has wide application to radioastronomy since it was the first organic acid found in interstellar space. In this work, the infrared absorption spectrum of the nu1 band of deuterated formic acid (DCOOD) has been measured on a Bomem DA3.002 Fourier transform spectrometer in the wavenumber region 2560-2690 cm(-1) with a resolution of 0.004 cm(-1). A total of 292 infrared transitions have been assigned in this hybrid type A and B band centred at 2631.8736 +/- 0.0004 cm(-1). The assigned transitions have been fitted to give a set of eight rovibrational constants for the nu1 = 1 state with a standard deviation of 0.00078 cm(-1).

Rovibrational Analysis of nu(2) and 2nu(5) Bands of DCOOH by High Resolution FTIR Spectroscopy

The infrared absorption spectrum of the nu(2) band of deuterated formic acid (DCOOH) was recorded using a Bomem DA3.002 Fourier transform spectrometer in the wavenumber region 2130-2300 cm(-1) with an apodized resolution of 0.004 cm(-1). A total of 1024 transitions were assigned to this band which is hybrid type A and B, centered at 2219.6896 +/- 0.0002 cm(-1). As expected, the nu(2) band is coupled to 2nu(5) by a c-type Coriolis interaction. Both perturbed and unperturbed transitions were assigned and fitted to give seven rovibrational constants for the nu(2) = 1 state with a standard deviation of 0.00094 cm(-1) using Watson's A-reduced Hamiltonian in the I(r) representation. A c-type Coriolis interaction term between nu(2) and 2nu(5) was derived from the rovibrational analysis. The ratio of the transition moments, ||µ(b)/µ(a) ||, was found to be 1.42 +/- 0.10 for the hybrid band. Copyright 1999 Academic Press.

Rovibrational Constants for the nu(6) and 2nu(9) Bands of HCOOD by Fourier Transform Infrared Spectroscopy

The Fourier transform infrared spectrum of the nu(6) and 2nu(9) bands of deuterated formic acid (HCOOD) was recorded with an apodized resolution of 0.004 cm(-1) in the frequency range of 930-1040 cm(-1). These two bands with band centers 40 cm(-1) apart were mutually coupled by Coriolis and Fermi interactions. By fitting a total of 1076 infrared transitions of both nu(6) and 2nu(9) with a standard deviation of 0.00075 cm(-1) using a Watson's A-reduced Hamiltonian in the I(r) representation with the inclusion of c-type Coriolis and a Fermi-resonance term, two sets of rovibrational constants for v(6) = 1, and v(9) = 2 states were derived for the first time. Both nu(6) and 2nu(9) bands are A type with band centers at 972.8520 +/- 0.0001 and 1011.6766 +/- 0.0001 cm(-1), respectively. Copyright 1999 Academic Press.

FTIR Spectrum of the nu4 Band of DCOOD

The FTIR spectrum of the nu4 band of deuterated formic acid (DCOOD) has been measured with a resolution of 0.004 cm-1 in the frequency range of 1120 to 1220 cm-1. A total of 1866 assigned transitions have been analyzed and fitted using a Watson's A-reduced Hamiltonian in the Ir representation to derive rovibrational constants for the upper state (v4 = 1) with a standard deviation of 0.00036 cm-1. In the course of the analysis, the constants for the ground state were improved by a simultaneous fit of microwave frequencies and combination differences from the infrared measurements. Due to the relatively unperturbed nature of the band, the constants can be used to accurately calculate the infrared line positions for the whole band. Although the band is a hybrid type A and B, only a-type transitions were strong enough to be observed. The band center is at 1170.79980 +/- 0.00002 cm-1. Copyright 1999 Academic Press.

Analysis of High-Resolution FTIR Spectrum of the nu6 Band of H13COOH

The FTIR spectrum of the nu6 band of H13COOH has been collected at a resolution of 0.004 cm-1 in the frequency range of 1030-1160 cm-1. The nu6 band was analyzed to be an A-B hybrid band and perturbed by the nearby nu8 band through a-, and b-Coriolis coupling terms. Using a Watson's A-reduced Hamiltonian in the Ir representation, with the inclusion of a- and b-Coriolis resonances, a total of 3004 IR transitions of nu6 have been analyzed to provide rovibrational constants for the v6 = 1 state with a standard deviation of 0.00047 cm-1. The nu6 band was found to be centered at 1095.40365 +/- 0.00003 cm-1. Copyright 1999 Academic Press.

High-Resolution FTIR Spectrum of the nu5 Band of HCOOD

The high-resolution Fourier transform infrared spectrum of HCOOD has been measured in the nu5 region between 1120 and 1220 cm-1 with a resolution of 0.004 cm-1. As expected for an in-plane vibrational fundamental mode, the nu5 band is a hybrid band consisting of both a-type and b-type transitions. Using the Watson's A-reduced Hamiltonian in the Ir representation, 1943 infrared transitions have been assigned and fitted to give 12 rovibrational constants for the v5 = 1 state. The nu5 band is primarily A type with a band center at 1177.09378 +/- 0.00002 cm-1. It is found that nu5 is slightly perturbed by the nearby 2nu7. About 90 perturbed transitions were identified. Copyright 1998 Academic Press.

Molecular genetics of cystinuria: mutation analysis of SLC3A1 and evidence for another gene in type I (silent) phenotype

BACKGROUND

Cystinuria is a hereditary disorder that affects luminal transport of cystine and dibasic amino acids in kidney and small intestine. Three subtypes have been defined on the basis of urinary excretion of cystine in obligate heterozygotes. Mutations in the SLC3A1 gene have been associated with the Type I phenotype.

METHODS

We investigated 20 cystinuria patients from Quebec (8 Type I/I, 9 Type I/III and 3 Type II/N) for mutations in SLC3A1. DNA was studied by Southern blotting and by the single strand conformation polymorphism (SSCP) protocol to identify mutations. Expression of mutations in Xenopus oocytes was performed to confirm the effect of missense mutations on cystine uptake.

RESULTS

Six novel mutations (2 large deletions, a 2 bp deletion and 3 single bp substitutions) were identified on the Type I allele. Four missense mutations (T216M, S217R, R270L and I618M) were expressed in vitro; the first three changes significantly decreased uptake.

CONCLUSIONS

Combined with our previous work, we have identified 15/16 mutations in SLC3A1 on Type I alleles in the eight Type I/I patients, but only one SLC3A1 mutation on the nine Type I alleles of the Type I/III patients. Therefore, we propose that the Type I phenotype could be caused by mutations in other, as yet unidentified cystinuria genes.

Cystinuria subtype and the risk of nephrolithiasis

BACKGROUND

Cystinuria patients may be classified into several subgroups based on the urinary phenotype of heterozygotes. However, the relative risk for nephrolithiasis and the prevalence of SLC3A1 mutations in these subgroups are unknown.

METHODS

Urinary cystine excretion, age at onset of nephrolithiasis and nature of SLC3A1 mutations were assessed prospectively in 23 cystinuria patients identified primarily through the Quebec Newborn Screening Program. Probands were classified as to cystinuria subtype on the basis of parental urinary cystine excretion.

RESULTS

For classical Type I/I cystinuria, both parents excrete cystine in the normal range and probands carry two mutations of the SLC3A1 gene in nearly every case. Between ages 1 to 7 years, mean cystine excretion was high (4566 +/- 480 microns cystine/g creatinine) and exceeded the theoretic threshold for solubility on 70% of visits. Four of eight Type I/I patients began forming stones in the first decade. Type I/III patients (N = 12) excreted less cystine (1544 +/- 163 mumol cystine/g creatinine), exceeded the threshold of urinary cystine solubility less frequently (22% of visits) and had no nephrolithiasis in the first decade; one formed a stone at age 16 years. Only one SLC3A1 mutation was identified in this group. Two Type II/N cystinuria children were identified. In these families, the same level of relatively high excretion (> 600 mumol cystine/g creatinine) was noted in two or three generations, but no SLC3A1 mutations were identified.

CONCLUSIONS

Classical recessive Type I/I cystinuria is genetically and phenotypically distinct from the other subtypes (Type I/III and Type II/N) identified in our population.