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PubMed2006

Value of ovarian reserve testing before IVF: a clinical decision analysis.

BACKGROUND: To assess the value of testing for ovarian reserve prior to a first cycle IVF incorporating patient and doctor valuation of mismatches between test results and treatment outcome. METHODS: A decision model was developed for couples who were considering participation in an IVF programme. Three strategies were evaluated: (I) withholding IVF without prior testing, (II) testing for ovarian reserve, and then deciding on IVF treatment if ovarian reserve was estimated to be sufficient, and (III) treatment with IVF without prior ovarian reserve testing. The outcome considered was the birth of a child. The valuation of the combination of the strategy conducted and the outcome accomplished was expressed on a distress scale in units of 'IVF cycles that were performed in vain'. Correct treatment with IVF and correct withholding of IVF were considered to bring no distress. The distress of withholding IVF in case pregnancy occurred is consequently specified by the ratio of the expected distress after incorrect withholding IVF to the expected distress after incorrect performing IVF (distress ratio). We interviewed both patients and doctors to determine realistic estimates for this distress ratio. RESULTS: The value of testing for ovarian reserve depends strongly on the expected pregnancy rate after IVF as well as on the valuation of the incorrect decisions from testing. For realistic ranges of the success rate after IVF and for distress ranges as were measured, treatment of all couples without testing was found to generate less distress than testing for ovarian reserve. The sensitivity and specificity of testing for ovarian reserve has to improve to 50 and 96% respectively, to make testing a valuable strategy. CONCLUSION: Based on the decision analysis, where current test accuracy and preference inventory among patients and physicians were used, testing for ovarian reserve seems not useful for current IVF programmes.

Attitude↗
PubMed2002

Incorporating spatial criteria in optimum reserve network selection.

Considering the spatial location of sites that are to be selected for inclusion in a protected reserve network may be necessary to facilitate dispersal and long-term persistence of species in the selected sites. This paper presents an integer programming (IP) approach to the reserve network selection problem where spatial considerations based on intersite distances are taken into account when selecting reserve sites. The objective is to reduce the fragmentation of preserved sites and design a compact reserve network. Two IP formulations are developed which minimize the sum of pairwise distances and the maximum intersite distance between all sites in the reserve network, respectively, while representing all species under consideration. This approach is applied to a pond invertebrate dataset consisting of 131 sites containing 256 species in Oxfordshire, UK. The results show that significant reductions in reserve fragmentation can be achieved, compared with spatially unrestricted optimum reserve selection, at the expense of a small loss in reserve efficiency.

Algorithms↗
PubMed2006

Sensitivity of marine-reserve design to the spatial resolution of socioeconomic data.

Socioeconomic considerations should have an important place in reserve design. Systematic reserve-selection tools allow simultaneous optimization for ecological objectives while minimizing costs but are seldom used to incorporate socioeconomic costs in the reserve-design process. The sensitivity of this process to biodiversity data resolution has been studied widely but the issue of socioeconomic data resolution has not previously been considered. We therefore designed marine reserves for biodiversity conservation with the constraint of minimizing commercial fishing revenue losses and investigated how economic data resolution affected the results. Incorporating coarse-resolution economic data from official statistics generated reserves that were only marginally less costly to the fishery than those designed with no attempt to minimize economic impacts. An intensive survey yielded fine-resolution data that, when incorporated in the design process, substantially reduced predicted fishery losses. Such an approach could help minimize fisher displacement because the least profitable grounds are selected for the reserve. Other work has shown that low-resolution biodiversity data can lead to underestimation of the conservation value of some sites, and a risk of overlooking the most valuable areas, and we have similarly shown that low-resolution economic data can cause underestimation of the profitability of some sites and a risk of inadvertently including these in the reserve. Detailed socioeconomic data are therefore an essential input for the design of cost-effective reserve networks.

Animals↗
PubMed2001

Ecological degradation in protected areas: the case of Wolong Nature Reserve for giant pandas.

It is generally perceived that biodiversity is better protected from human activities after an area is designated as a protected area. However, we found that this common perception was not true in Wolong Nature Reserve (southwestern China), which was established in 1975 as a "flagship" protected area for the world-renowned endangered giant pandas. Analyses of remote sensing data from pre- and post-establishment periods indicate that the reserve has become more fragmented and less suitable for giant panda habitation. The rate of loss of high-quality habitat after the reserve's establishment was much higher than before the reserve was created, and the fragmentation of high-quality habitat became far more severe. After the creation of the reserve, rates of habitat loss and fragmentation inside the reserve unexpectedly increased to levels that were similar to or higher than those outside the reserve, in contrast to the situation before the reserve was created.

Animals↗
PubMed2004

Relation between left ventricular contractile reserve during low dose dobutamine echocardiography and plasma concentrations of natriuretic peptides.

BACKGROUND: In ischaemic cardiomyopathy, raised plasma concentrations of natriuretic peptides are associated with a poor long term prognosis, while the presence of contractile reserve is a favourable sign. OBJECTIVE: To assess the relation between plasma natriuretic peptides and contractile reserve. DESIGN: Prospective observational study. SETTING: Tertiary referral centre. PATIENTS: 66 consecutive patients undergoing low dose dobutamine stress echocardiography to evaluate contractile reserve in regions with contractile dysfunction at rest, divided into two groups: group 1, 31 patients with ischaemic cardiomyopathy (left ventricular ejection fraction < or = 40%) and heart failure symptoms; group 2, 35 patients with normal left ventricular function. MAIN OUTCOME MEASURES: Plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), measured using immunoradiometric assays. Contractile reserve was defined as an improvement in segmental wall motion score during infusion of low dose dobutamine. RESULTS: Plasma ANP and BNP concentrations were higher in group 1 than in group 2 (mean (SD): ANP, 17.8 (32.8) v 7.2 (9.7), p < 0.005; BNP, 24.4 (69.0) v 5.0 (14.3) pmol/l, respectively; p < 0.001). In group 1, the presence of contractile reserve was inversely related to ANP and BNP levels; however, patients with contractile reserve had lower ANP and BNP concentrations than patients without contractile reserve (ANP, 14.2 (9.1) v 24.2 (44.2), p < 0.05; BNP, 20.2 (25.5) v 37.5 (93.8) pmol/l, respectively; p < 0.05). CONCLUSIONS: Plasma natriuretic peptide concentrations are raised in patients with left ventricular dysfunction, but in the presence of preserved myocardial contractile reserve, relatively low levels of ANP and BNP are present.

Echocardiography, Stress↗
PubMed1993

Coronary flow reserve in patients with chest pain and normal coronary arteries.

BACKGROUND: Many studies have shown that coronary flow reserve is reduced in patients with chest pain and angiographically normal coronary arteries. The methods used to assess coronary blood flow have varied, but in nearly all reports dipyridamole has been used to bring about vasodilatation. This study was designed to assess whether the apparent impairment of coronary flow reserve seen with dipyridamole could be reproduced with either papaverine or adenosine, which induce maximum coronary blood flow by different mechanisms. METHODS: 25 patients with chest pain and angiographically normal coronary arteries were studied with an intracoronary Doppler flow probe and quantitative angiography to determine epicardial coronary artery area, coronary blood flow velocity, coronary flow reserve, and coronary vascular resistance index (CVRI, the ratio of resistance after intervention to basal resistance). All patients received papaverine 8 mg. Eight patients with positive exercise tests received intracoronary papaverine (8 and 10 mg), intracoronary adenosine (6, 20, 60 micrograms), and high-dose intravenous dipyridamole (0.84 mg/kg). RESULTS: The velocity ratio (peak after intervention: baseline) (mean (SEM)) after 8 mg papaverine was 3.3 (0.2) (n = 25) and the coronary flow reserve was 4.1 (0.3) (n = 25). There were no differences between patients with a positive (n = 16) or negative (n = 9) exercise test. In eight patients coronary flow reserve was measured after increasing doses of papaverine, adenosine, and dipyridamole. Coronary flow reserve was 4.5 (0.3) with papaverine, 4.8 (0.3) with adenosine, and 3.5 (0.4) with dipyridamole (p = 0.08 v papaverine and adenosine). CVRI was 0.22 (0.01) with papaverine, 0.21 (0.02) with adenosine, and 0.29 (0.03) with dipyridamole (p < 0.05 v papaverine, p = 0.09 v adenosine). CONCLUSIONS: These results indicate that measurement of coronary flow reserve and CVRI in patients with chest pain and normal coronary arteries depends on the pharmacological stimulus. Normal values were obtained with papaverine in all patients, irrespective of the exercise test response. In patients with a positive exercise test significantly lower values were obtained with dipyridamole than with papaverine, or adenosine. The reported impairment of coronary flow reserve in patients with angina and normal coronary arteries may reflect the variability in response to different pharmacological agents. The mechanism underlying this variability is unknown, but may involve an abnormality of adenosine metabolism in the myocardium.

Adenosine↗
PubMed2001

Noninvasive quantification of coronary blood flow reserve in humans using myocardial contrast echocardiography.

BACKGROUND: We hypothesized that coronary blood flow (CBF) reserve could be quantified noninvasively in humans using myocardial contrast echocardiography (MCE). METHODS AND RESULTS: Eleven patients with normal epicardial coronary arteries (group I) and 19 with single-vessel coronary stenosis (group II) underwent quantitative coronary angiography, MCE, and CBF velocity measurements at rest and during intravenous adenosine infusion. In group I patients, MCE-derived myocardial blood flow (MBF) velocity reserve (2.4+/-0.08) was similar to CBF velocity reserve using a Doppler flow wire (2.4+/-1.1). Patients with a single risk factor had a significantly higher MBF reserve (3.0+/-0.89) than those with >/=2 risk factors (1.7+/-0.22). In group II patients, significant differences were found in MBF velocity reserve in patients with mild (<50%), moderate (50% to 75%), or severe (>75%) stenoses (2.2+/-0.40, 1.6+/-0.65, and 0.55+/-0.19, respectively; P=0.005). A linear relation was found between flow velocity reserve determined using the 2 methods (r=0.76, P<0.001), and a curvilinear relation was noted between the percent coronary stenosis measured using quantitative coronary angiography and velocity reserve using both methods. CONCLUSIONS: CBF reserve can be measured in humans using MCE. This method may allow the noninvasive assessment of coronary stenosis severity and the detection of microvascular dysfunction.

Adult↗
PubMed1990

Nonuniform loss of regional flow reserve during myocardial ischemia in dogs.

To determine whether coronary vasodilator reserve that persists during myocardial ischemia is present in all left ventricular regions, we measured regional blood flow in 192 left ventricular pieces (mean weight, 201 mg) in each of eight dogs by using radioactive microspheres while perfusing the left main coronary artery at 70, 50, 40, and 30 mm Hg. Flows were measured before and during adenosine infusion to determine flow reserve. Perfusion at 40 and 30 mm Hg produced ischemia in all dogs. At 70 mm Hg, 100% of left ventricular regions had significant flow reserve, compared with 92%, 55%, and 8% during perfusion at 50, 40, and 30 mm Hg, respectively. A greater amount of flow reserve and a greater number of regions responded to adenosine in the subepicardium than in the subendocardium at 50, 40, and 30 mm Hg. We conclude that coronary flow reserve persists in only a subset of left ventricular regions during ischemia and that the number of regions with persistent flow reserve decreases with perfusion pressure. These findings may best be explained by a model in which regional ischemia is a maximal coronary vasodilator and persistent pharmacological vasodilator reserve seen when global markers indicate ischemia simply reflects persistent endogenous flow reserve in myocardial regions not yet ischemic.

Adenosine↗
PubMed2006

Marine reserve design: optimal size, habitats, species affinities, diversity, and ocean microclimate.

The design of marine reserves is complex and fraught with uncertainty. However, protection of critical habitat is of paramount importance for reserve design. We present a case study as an example of a reserve design based on fine-scale habitats, the affinities of exploited species to these habitats, adult mobility, and the physical forcing affecting the dynamics of the habitats. These factors and their interaction are integrated in an algorithm that determines the optimal size and location of a marine reserve for a set of 20 exploited species within five different habitats inside a large kelp forest in southern California. The result is a reserve that encompasses approximately 42% of the kelp forest. Our approach differs fundamentally from many other marine reserve siting methods in which goals of area, diversity, or biomass are targeted a priori. Rather, our method was developed to determine how large a reserve must be within a specific area to protect a self-sustaining assemblage of exploited species. The algorithm is applicable across different ecosystems, spatial scales, and for any number of species. The result is a reserve in which habitat value is optimized for a predetermined set of exploited species against the area left open to exploitation. The importance of fine-scale habitat definitions for the exploited species off La Jolla is exemplified by the spatial pattern of habitats and the stability of these habitats within the kelp forest, both of which appear to be determined by ocean microclimate.

California↗
PubMed2000

[Evaluation of coronary flow reserve in patients with vasospastic angina].

OBJECTIVES: The presence of microvascluar impairment was evaluated in 154 patients with vasospastic angina identified by the acetylcholine provocation test. METHODS: Coronary flow reserve was evaluated with a Doppler flow guidewire in 128 vessels of 72 patients with chest pain, but no significant coronary stenosis(less than 50% stenosis) and no clinical factors that affect coronary flow reserve. Coronary flow reserve was obtained from the ratio of adenosine triphosphate-induced maximum/baseline averaged peak velocity. These vessels were classified into 2 categories according to whether acetylcholine-induced vasospasm was positive or negative. Vasospasm positive was defined as more than 90% stenosis provoked with chest pain and/or ischemic ST change. Positive vessels were subdivided according to focal or diffuse vasospasm. These vessels were also classified into 2 other categories according to whether vasospasm in the distal artery was positive or negative. RESULTS: Coronary flow reserve was significantly lower in vessels with vasospasm than in vessels without vasospasm in patients without vasospasm(2.9 +/- 0.8 vs 3.6 +/- 1.0, p = 0.0005). Coronary flow reserve was significantly lower in vessels without vasospasm in patients with vasospasm than in vessels without vasospasm in patients without vasospasm(3.0 +/- 0.8 vs 3.6 +/- 1.0, p = 0.03). There was no significant difference in coronary flow reserve between vessels with vasospasm and vessels without vasospasm in patients with vasospasm(2.9 +/- 0.8 vs 3.0 +/- 0.8, p = 0.8). There was no significant difference in coronary flow reserve between focal and diffuse vasospasm(3.2 +/- 0.8 vs 2.9 +/- 0.8, p = 0.3). Coronary flow reserve was significantly lower in vessels with vasospasm in the distal artery than in vessels without vasospasm in the distal artery (2.8 +/- 0.8 vs 3.4 +/- 1.0, p = 0.004). CONCLUSIONS: Patients with vasospastic angina have microvascular impairment in both vessels with vasospasm, and vessels without vasospasm. Microvascular impairment is prominent in vessels with vasospasm in the distal artery.

Acetylcholine↗
PubMed2003

[Measurement of coronary reserve by high-frequency transthoracic Doppler ultrasonography: indications and results].

Coronary flow reserve is the ability of coronary flow to increase above its basal value when the coronary vascular bed is maximally dilated. It is a global parameter of coronary flow, which is early altered in the presence of epicardial coronary artery stenosis or a coronary microcirculation disorder. Until now, clinical use of coronary flow reserve has been hampered by the lack of an easy, reliable and non-invasive method. Recently developed high-frequency transthoracic Doppler echocardiography now allows non-invasive assessment of coronary flow reserve. After an initial learning curve, it is possible to study coronary flow, essentially in the left anterior descending artery. Coronary flow reserve is expressed as the ratio of maximal hyperaemic to basal mean coronary velocity. Maximal hyperaemic flow is obtained with adenosine. Clinical applications of coronary flow reserve are numerous. Coronary flow reserve enables the assessment of hemodynamic relevance of a moderate coronary stenosis. Detection of coronary restenosis is also possible by repeated non-invasive measurement of coronary flow reserve. Moreover, evaluation of the microcirculation is of crucial importance in order to appreciate myocardial reperfusion following successful recanalisation on the infarct-related artery. Transthoracic Doppler echocardiography could allow identification of "no-reflow" by analysis of coronary flow pattern and coronary flow reserve. Furthermore, transthoracic Doppler echocardiography constitutes one of the only available and simple means to evaluate microcirculatory disorders (hypertension, diabetes,...). Finally, the possibility of non-invasive follow-up of arterial bypasses constitutes a major advantage of this technique.

Coronary Stenosis↗
PubMed2004

Correlation of angiographic circulation time and cerebrovascular reserve by acetazolamide-challenged single photon emission CT.

BACKGROUND AND PURPOSE: Although cerebral circulation time (CCT) is one of the main parameters in cerebral blood flow measurements, its clinical significance is controversial. To assess the importance of CCT by using a nondiffusible indicator, we studied the relationship between angiographic CCT and cerebrovascular reserve. METHODS: Twenty-eight patients, each with a unilateral occlusive lesion in the internal carotid artery or middle cerebral artery, were examined. To assess the CCT, the regional arteriocapillary circulation time (rACCT) was measured by angiography and the ratio of the value on the occlusive side to the value on the contralateral side was calculated as the rACCT ratio. To estimate the cerebrovascular reserve, acetazolamide-challenged single photon emission CT was used. Patients with a decreased cerebrovascular reserve were defined as the "poor reserve" group, and those without a decrease were defined as the "normal reserve" group. The ratio of the radioactivity count on the occlusive side to the count on the contralateral side was calculated as the asymmetry index, and the proportion of the acetazolamide-challenged asymmetry index to the baseline asymmetry index was defined as the regional reactivity index. RESULTS: The rACCT ratio in the poor reserve group (n = 19) was significantly (P <.001) larger than that in the normal reserve group (n = 9), and a significant correlation (r = -0.83, P <.01) was found between the rACCT ratio and the regional reactivity index. CONCLUSION: The angiographic CCT and the cerebral vasoreactivity to acetazolamide on single photon emission CT were well correlated, suggesting that measurement of the CCT by using a nondiffusible indicator could be used as an index of cerebrovascular reserve.

Acetazolamide↗
PubMed1991

[Coronary flow reserve and stenosis as the determinant of exercise capacity in patients with stable effort angina].

The coronary flow reserve was evaluated in 33 patients with stable effort angina and single vessel disease of the left anterior descending artery. We used a catheter-tip Doppler flow probe with injection of contrast media to the vessel in order to induce so-called reactive hyperemia. The reactive change was used as an index of the flow reserve of the coronary artery. In 15 patients out of 33, PTCA was performed and the change in the coronary flow reserve was evaluated. There was a good correlation between the coronary flow reserve and the exercise capacity in the treadmill ECG exercise test. As theoretically expected, the exercise capacity was determined by the coronary flow reserve. There was a poor correlation between the degree of stenosis shown in coronary arteriography and the coronary flow reserve. The degree of stenosis did not relate with the exercise capacity. The coronary flow reserve was increased with the procedure of PTCA. Though the patho-anatomic findings in coronary angiography give us important information to evaluate patients with ischemic heart disease, we concluded that these findings were still insufficient to allow us to estimate the flow reserve in the coronary artery. The exercise capacity did not relate well with the degree of stenosis.

Adult↗
PubMed1991

[The recovery of the kidney filtration functional reserve in diabetes mellitus patients on captopril treatment].

Overall 42 normotensive patients suffering from type I diabetes mellitus without proteinuria were examined for the effect of hyperfiltration on renal glomerular function and for changes in glomerular function seen during medicamentous treatment of hyperfiltration. Glomerular function was evaluated from the basal level of glomerular filtration (GF), the status of filtration reserves (i. e. according to the dynamics of the GF level in response to oral protein administration), and from the magnitude of albuminuria. Three groups of diabetes mellitus patients were distinguished: with filtration reserves, with decreased filtration reserves, and with no reserves. All the three groups did not differ in the age, diabetes standing or the degree of carbohydrate disorders compensation (HBA1c). Still, the patients with no filtration reserves significantly differ from the other groups with a high level of GF and albuminuria. In 9 patients, a study was made of the effect produced by captopril (an inhibitor of the angiotensin-transforming enzyme) on filtration reserves and albuminuria. After 3 to 6 months of the treatment five patients with no filtration reserves manifested a fall of the basal level of GF down to normal, the recovery of filtration reserves, and a decline of albuminuria. It is assumed that elimination of hyperfiltration due to the treatment with the inhibitors of the angiotensin-transforming enzyme may be an effective means of diabetic nephropathy prevention.

Adolescent↗
PubMed1977

[Left ventricular contraction reserve in coronary heart disease. Evaluation, quantification and prognostic value (author's transl)].

Regional and overall left ventricular contraction reserve was studied in 14 patients with coronary heart disease, in 5 healthy subjects and in 4 patients before and after aorto-coronary bypass surgery. Quantification of overall contraction was based on ventricular volumes and ejection fraction. Regional contraction reserve was calculated with the hemiaxis method and a ventricular score. Contraction reserve under nitroglycerin and in postextrasystolic beats was compared. For routine quantification of contraction reserve the ventricular score is recommended. For research purposes the hemiaxis method is to be preferred. Postextrasystolic beats are better suited for analysis of contraction reserve than are angiograms following administration of nitroglycerin. This is due to the minor expense of the procedure, furthermore, postextrasystolic beats allow better differentiation between contracting and non-contracting areas. Left ventricular contraction reserve is larger in patients with coronary heart disease, angina pectoris and ischemic reactions in the exercise ECG than in control patients. These findings are based on overall and on regional volume parameters. A quantitatively greater improvement in contraction could be provoked in the anterior wall than in the posterior wall. Regional contraction improved significantly in most cases either in the anterior wall or in the posterior wall; rarely it improved simultaneously in both left ventricular regions. In a few cases contraction deteriorated in one area with a simultaneous improvement in the opposite area. Overall and regional ventricular function, as assessed preoperatively by contraction reserve determinations could not be completely regained in normal beats after successful bypass surgery. Differences in the regional contraction reserve seemed to be mainly due to varying degrees of ischemia and scarring.

Angina Pectoris↗
PubMed1978

[Contractile and relaxation reserve of the left ventricle. III. Patients with cardiomyopathy (author's transl)].

Seven of 22 patients with cardiomyopathy increased maximal rate of left ventricular pressure rise (max dP/dt) above 3200 mm Hg/s and dP/dt/P above 60/s. Relaxation reserve was normal with an increase of min dP/dt above 2400 mm Hg/s.--In 15 patients contractile and relaxation reserve was reduced. In congestive cardiomyopathy, contractility and relaxation reserve were equally reduced. Left ventricular enddiastolic pressure increased during exercise slightly or not (grade 1). Enddiastolic volume was elevated to 173 +/- 50 ml/1.73 m2 and endsystolic volume to 63 +/- 22 ml/1.73 m2; ejection fraction and mean circumferential fiber shortening were reduced (61 +/- 17%; 1.3 +/- 0.9 circ/s). In hypertrophic cardiomyopathy without obstruction, contractile and relaxation reserve and ejection phase parameters could be found to be normal. Enddiastolic pressure at rest was elevated. In severe cases, contractile and relaxation reserve were markedly reduced and enddiastolic pressure increased to a greater extent than in congestive cardiomyopathy. In addition, relaxation reserve was reduced, especially in patients with excessive hypertrophy of the myocardium. These had abnormal (grade 2) and pathological reaction to exercise: contractile and relaxation reserve were decreased and enddiastolic pressure (grade 3) increased. Left ventricular contractility was found to be almost normal in patients with hypertrophic obstructive cardiomyopathy. This was the case despite increases in enddiastolic pressure. Contractile reserve was reduced, however, in patients with excessive hypertrophy. Diastolic filling was impeded during exercise.--Measuring left ventricular function during exercise, different types of cardiomyopathy correlate with typical hemodynamic alterations.

Adult↗
PubMed1994

Acute protein loading in the assessment of renal reserve.

Functional renal reserve is a measure of the capacity of the kidney to increase the glomerular filtration in response to the stimulus of a protein meal or amino acid infusion. The aim of this study was to evaluate the usefulness of protein meal test to measure functional renal reserve in normal subjects and various groups of renal patients. One hundred and twenty five subjects from the Nephrology Clinic, Kuala Lumpur General Hospital were subjected to a protein loading test to measure their renal reserve. Each subject had to eat a 100 gram cooked chicken meat and timed 2 hours urine collections before and after the test meal were done to measure the creatinine clearances. The 62 healthy subjects showed a mean renal reserve (creatinine clearance after protein loading-baseline creatinine clearance) of 31.0 ml/min. The 31 subjects with various kidney diseases showed a mean renal reserve of 13.5 ml/min. The 19 renal transplant recipients showed renal reserve of 13.2 ml/min. The 12 nephrectomised donors showed renal reserve of 5.4ml/min. Renal reserve may be used to assess suitability of living related transplant donor for nephrectomy.

Adult↗
PubMed1996

Relationship of thallium-201 clearance on exercise stress myocardial scintigraphy to coronary flow reserve in patients with coronary artery disease.

OBJECTIVE: We evaluated thallium-201 (201Th) clearance measurement during exercise myocardial scintigraphy in patients with coronary artery disease, for the assessment of coronary circulatory function and diagnosis. DESIGN: The clearance rate of 201Th was compared with the coronary flow reserve measured by Doppler coronary flow velocimetry. METHODS: We selected 20 patients who had chronic stable angina with single-vessel coronary artery disease of the left anterior descending artery (LAD) and underwent percutaneous transluminal coronary angioplasty (PTCA). Ten control patients had atypical chest pain but no detectable heart disease. Regional net clearance of 201Th was measured from the early and delayed bull's-eye images of 201Th exercise stress single photon emission tomography (SPECT). Using a Doppler catheter, we also measured coronary flow reserve of the LAD, which was obtained by the intracoronary administration of papaverine. RESULTS: The net 201Th clearance in the anterior wall myocardium in the patients with coronary artery disease before PTCA was significantly less than that in the controls. At follow-up angiography after successful PTCA, it increased. The coronary flow reserve before PTCA was also lower than that in the controls. It was increased immediately after PTCA, and was more markedly increased at the follow-up angiography. Before PTCA, regional net clearance in the anterior myocardium was correlated with the coronary flow reserve of the LAD. The ratio for the net clearance of the anterior myocardium at follow-up angiography to that before PTCA was also correlated with the ratio for coronary flow reserve. CONCLUSIONS: In patients with coronary artery disease, the regional 201Th clearance in the ischaemic area measured by exercise 201Th SPECT is correlated with the coronary flow reserve of the affected artery. Moreover, the increase in the clearance rate after PTCA is also correlated with that in the coronary flow reserve. Thus the measurement of regional 201Th clearance might be a useful non-invasive method of estimating of the coronary flow reserve.

Analysis of Variance↗