Patients undergoing invasive coronary angiography after a positive single-photon emission computed tomography or a positive stress cardiac magnetic resonance - What to expect at the cath lab

Funding Acknowledgements

Type of funding sources: None.

Background

 Randomized controlled trials comparing stress cardiac magnetic resonance (CMR) and single-photon emission computed tomography (SPECT) suggest similar diagnostic accuracy for detecting obstructive coronary artery disease (CAD). However, there are few data on whether or not this remains true in routine clinical practice.

The aim of this study was to assess the clinical and angiographic characteristics of patients undergoing invasive coronary angiography (ICA) after a positive stress CMR or positive SPECT, and to compare their positive predictive value with published results from the CE-MARC trial.

Methods

In this retrospective tertiary-center analysis, we included 429 patients (mean age 67 ± 10 years, 28% women, 42% diabetic) undergoing ICA between January 2016 and December 2020, after a positive stress CMR or positive SPECT. Regarding stress test, an adenosine protocol was performed in all stress CMR and in 76.4% (n = 272) of stress SPECT. 

Stress test results, including ischemia location and severity, were classified as reported by their primary readers. Patients with missing data on key variables, and those in whom microvascular disease was considered likely in the original stress test report were excluded. Obstructive CAD was defined as any coronary artery stenosis ≥ 50% in a vessel compatible with the ischemic territory on stress testing.

Results

Out of the total 429 patients, 356 (83%) were referred after a positive SPECT, and 73 (17%) after a positive stress CMR. Patients did not differ regarding age, cardiovascular risk factors, previous revascularization or left ventricular dysfunction, but patients with SPECT were more frequently male (p = 0.046). Overall, 320 patients (75%) had obstructive CAD on ICA. The prevalence of obstructive CAD was similar in patients with positive SPECT vs. positive stress CMR (76.1% vs. 80.8%, respectively, p = 0.385). There were also no significant differences in the prevalence of left main or 3-vessel disease (9.0% vs. 9.6%, p = 0.871, and 19.7% vs. 23.3% p = 0.483, respectively). Revascularization was performed or planned in 59.3% of patients in the SPECT group, and 52.1% of those in the stress CMR group (p = 0.255). The positive predictive values of both techniques were similar to those reported in the CE-MARC trial (Figure), and would increase to 88.1% and 89.4% for SPECT and stress CMR, respectively, if patients reported as having only mild ischemia were excluded.

Conclusion

In this tertiary center analysis, stress CMR and SPECT showed similar positive predictive values, comparable to those reported in the CE-MARC trial.

Prognosis in patients with left bundle branch block and normal dipyridamole thallium-201 scintigraphy

BACKGROUND

The presence of complete left bundle branch block (LBBB) is commonly associated with a poorer prognosis, especially in patients with coronary artery disease (CAD). In the general population with suspected CAD and normal intraventricular conduction, a normal dipyridamole-thallium scintigraphy is a strong marker of a favorable outcome.

OBJECTIVE

Our objective was to assess the prognosis in patients with LBBB and a normal dipyridamole thallium-201 scintigram.

POPULATION AND METHODS

Patients with complete LBBB and normal myocardial perfusion on dipyridamole SPECT thallium-201 scintigraphy performed in our center for suspected CAD between 1988 and 1995 were monitored for clinical events.

RESULTS

Sixty-nine patients (36 women and 33 men) with a mean age of 59 years (range 56 to 61) were monitored for a mean period of 33 months (range 25 to 35). During this period, 4 patients had unstable angina, 2 of whom underwent myocardial revascularization. There were no deaths or myocardial infarction. All events occurred at least 2 years after the thallium-201 scintigraphy.

CONCLUSION

The presence of a normal myocardial perfusion with dipyridamole thallium-201 scintigraphy in this group of patients with suspected CAD and LBBB was associated with a very good prognosis, a low rate of clinical events occurring only 2 years after the myocardial scintigraphy, and no hard events.

[Myocardial infarction in patients with single-vessel disease: are there clinical or angiographic markers of viability?]

OBJECTIVE

To assess whether some of the clinical and angiographic variables usually associated with the severity of coronary artery disease could be considered as markers of viability after myocardial infarction.

PATIENTS

We studied 41 patients with previous Q wave infarction and single-vessel coronary artery disease.

METHODS

Patients were studied with thallium-201 SPECT, two imaging acquisitions were performed: stress and reinjection three to four hours later under nitroglycerin effect. Perfusion and viability were compared to clinical and angiographic variables, including the degree of patency and colateralization.

RESULTS

In the infarct related area, 66 % of the 177 perfusion defects were considered reversible (definite in 40 %). In patient analysis, 28 patients were considered as having reversibility (18 with definite and 10 with possible reversibility). None of the clinical or stress test variables were significantly associated with reversibility; all these variables had extremely poor negative predictive values and only stress-induced ST depression had a reasonable positive predictive value (85 %). There was no association between TIMI grade and reversibility. In segments supplied by a TIMI 0 artery, a higher rate of fixed perfusion defects was associated with the absence of collateral circulation (75 % vs 22%; p < 0.013). Furthermore, severe impairment of contractility did not predict absence of viability, we identified as viable 55 % of akinetic segments and 29 % of segments classified angiographically as aneurysm.

CONCLUSIONS

These data suggest that common clinical and angiographic markers of severity of coronary artery disease are not useful in the detection of viable myocardium after myocardial infarction. Collateral circulation to occluded arteries was associated with viability, but its absence did not exclude it. Viability detection with appropriated tests, namely stress reinjection thalium scintigraphy should perhaps be considered as a routine procedure after myocardial infarction, especially when interventional therapy is to be considered.

[The 3-year prognosis of patients with suspected coronary disease and a normal myocardial scintigraphy with thallium-dipyridamole]

OBJECTIVES

To assess the 3-year prognosis of patients with suspected coronary artery disease and a normal dipyridamole-thallium scintigram.

POPULATION

43 patients, 16 male and 27 female, mean age 55.8 +/- 9.2 years with suspected coronary artery disease. Forty-two patients had anginal complaints. There was a previous positive treadmill exercise test in 14 patients. All the patients had a normal dipyridamole-thallium SPECT.

METHODS

Dipyridamole was infused at a rate of 0.56 mg/kg in 4 minutes followed by 3 minutes of low-level cycloergometer exercise. Two mCi of thallium-201 were injected 3 minutes after the end of dipyridamole infusion. Stress and redistribution SPECT acquisitions were performed respectively 5-10 minutes and 4 hours after thallium-201 injection. The cardiac events during a 3-year follow-up were analysed.

RESULTS

No patient had unstable angina, PTCA, CABG or death. One patient suffered an inferior myocardial infarction 28 months after the scintigraphy. The event rate was 0.78% per patient per year.

CONCLUSION

Three-year prognosis in patients with suspected coronary artery disease after a normal dipyridamole thallium SPECT is excellent approaching that of the general population.

[Response of the left ventricular ejection fraction,assessed by by radionuclide angiography, to inotropic stimulation: its relationship with the reversibility of perfusion defects in thallium-201 scintigraphy with overload-reinjection protocol]

BACKGROUND

Reversibility of perfusion defects and left ventricular (LV) ejection fraction (LVEF) response to low-dose catecholamines may reflect complementary aspects of myocardial viability, in patients with CAD and LV dysfunction in whom revascularization is considered.

OBJECTIVE

To evaluate the relationship between LVEF response to inotropic stimulation with adrenaline (delta LVEF) and myocardial perfusion.

DESIGN AND SETTING

Prospective study in a cardiology department with referral for revascularization and transplantation.

PATIENTS

45 patients (pt) with compromised LVEF (< 45%) after myocardial infarction (MI).

METHODS

Radionuclide ventriculography at baseline and during graded adrenaline infusion until 12 micrograms/min: an empirical cut-off value of delta LVEF of 8% was used to define groups with (CR+) or without (CR-) contractile reserve. Stress-reinjection 201TI SPECT: perfusion was classified with a weighted score based on visual analysis of extent and intensity of thallium uptake in five major myocardial segments, with results expressed as percent of myocardium classified as normal (%N), with fixed defects (%F), and with reversibility (%R).

MAIN RESULTS

Groups CR+ (23 pt) and CR- (22 pt) had similar baseline LVEF (29.6 +/- 7.4 and 26.4 +/- 8.1), while delta LVEF was respectively 13.6 +/- 4.6 and 2.9 +/- 3.3. When compared to the other group, CR+ patients had, in average, 1.0 segment more with definite reversibility and 1.6 segments less with fixed defects; in terms of percentage of myocardium, CR+ patients had more extensive reversible areas (%R: 15.3 +/- 11.7 vs 4.7 +/- 5.0, p < 0.001), smaller irreversible areas (%F: 30.7 +/- 14.5 vs 45.6 +/- 16.1, p = 0.02) and similar extent of normal areas (54.0 +/- 14.6 vs 49.7 +/- 16.4). Patients with more extensive fixed defects had worse delta LVEF in response to adrenaline (p < 0.002, r = -0.45). Greater %R was positively correlated with delta LVEF (p < 0.02, r = 0.35). In all patients, delta LVEF with adrenaline was superior or equal to (%R/2)-10. No patient with %R > or = 15 had delta LVEF < 8%. However, ten patients had delta LVEF > or = 8% despite lesser degrees of %R.

CONCLUSION

Our data suggest a clear association between myocardial inotropic reserve and the extent of potentially viable myocardium (as evaluated by stress-reinjection thallium SPECT), in patients with left ventricular dysfunction after myocardial infarction. Further assessment is needed to clarify the relative role of radionuclide ventriculography with inotropic stimulation in viability evaluation, notably with inclusion of regional wall motion information and with reassessment of patients after revascularization, when performed.

[Effectiveness and safety of coronary vasodilation with adenosine triphosphate with thallium-201 for the diagnosis of coronary disease]

OBJECTIVE

To evaluate the accuracy and safety of pharmacologic stress testing with adenosine triphosphate (ATP) associated with thallium-201 scintigraphy for detection of coronary artery disease.

PATIENTS

We studied 44 patients, 35 male and 9 female with a mean age of 59 + 9 years. Previous myocardial infarction was present in 15 patients. Thirty-two patients underwent coronariography that revealed coronary artery disease in 28 patients.

METHODS

ATP (Stryadine) was infused at a rate of 140 micrograms/kg/min for 6 minutes and 2 mCi of thallium-201 was injected at the third minute. Stress and redistribution SPECT acquisitions were performed respectively 5-10 minutes and 4-6 hours after ATP infusion.

RESULTS

The incidence of side effects was 77% and chest pain was the most frequent (45%). Dyspnea occurred in 2 patients and only one patient presented transient first degree AV block. No serious or severe side effect occurred. In patients without myocardial infarction 14 of 16 patients with significant coronary artery disease had reversible perfusion defects demonstrated by ATP thallium-201 scintigraphy (sensitivity 88%) and all of 4 patients without significant coronary artery disease had normal myocardial perfusion (specificity 100%). The overall accuracy for detecting the presence of coronary artery disease was 90%. The test demonstrated an overall accuracy of 88% for detecting left anterior descending artery disease, 91% for circumflex artery disease and 80% for right coronary artery disease.

CONCLUSIONS

Pharmacologic stress with ATP associated with thallium-201 scintigraphy, is a safe and high accurate alternative to dipyridamole and adenosine for the diagnosis of coronary artery disease.

[Superiority of the reinjection method compared with the redistribution of thallium-201 in the evaluation of reversibility after myocardial infarction]

OBJECTIVE

To assess the relative capacity of thallium-201 reinjection (RI) and redistribution (RD) for detection of reversibility in patients after myocardial infarction.

DESIGN

We prospectively studied patients referred to myocardial scintigraphy for viability evaluation with stress, redistribution and reinjection images.

METHODS

Patients were studied with thallium-201 SPECT using three imaging acquisitions--stress, redistribution three to four hours later and reinjection 30-60 minutes after a second injection of thallium under nitroglycerin effect. Thallium uptake was classified in a 0 to 4 intensity scale in each of 13 myocardial segments and a score obtained. Reversibility was classified as "definite" if the increase in thallium uptake was > or = 2 in a myocardial segment and as "possible" if the increase was one.

PATIENTS

We studied 44 patients with previous myocardial infarction.

RESULTS

The perfusion score after stress was 37.3 +/- 6.0, improving to 39.8 +/- 6.7 after redistribution and to 43.6 +/- 7.6 after reinjection (p < 0.02 between RD and RI). RD identified reversibility in 38% and RI in 63% (p < 0.001) of the 232 segments with perfusion defects. RI showed reversibility in 39% (definite in 25% and possible in 14%) of the 137 fixed perfusion defects in RD. For the detection of reversibility RI was superior to RD in all sub-groups analyzed. We found a relationship the degree of collateral circulation in the infarct related artery and the amount of reversibility in the infarcted area.

CONCLUSIONS

These data suggest a clear superiority of reinjection over redistribution in thallium-201 scintigraphy for the detection of reversibility of perfusion defects after myocardial infarction, and must probably be considered as a routine procedure for myocardial viability assessment.

[Reversibility in perfusion scintigraphy after myocardial infarct: a comparison between the protocol of single-day rest-stress with 99mTc sestamibi and reinjection with thallium-201]

OBJECTIVE

To compare thallium-201 stress-reinjection SPECT (TL) and single-day rest-stress 99mTc-sestamibi SPECT (MIBI) for detection of reversibility of perfusion defects after Q-wave myocardial infarction.

DESIGN

Prospective study with the two scintigraphic methods.

PATIENTS

We studied 31 patients with previous Q-wave myocardial infarction referred for assessment of myocardial viability.

METHODS

Patients were studied with thallium-201 stress-reinjection SPECT and single-day rest-stress 99mTc-sestamibi SPECT. Tracer uptake was classified in a 0 to 4 intensity scale in each of 13 myocardial segments.

RESULTS

Segmental comparison indicated that the identification of perfusion defects was similar by the two methods. Some reversibility was present in 51% of TL perfusion defects and in 26% of MIBI perfusion defects (p < 0.001). Twenty-seven percent of fixed perfusion defects in MIBI showed some reversibility by TL, but only 8% of the fixed perfusion defects by TL were reversible by MIBI (p < 0.001). In infarct-related perfusion defects, TL showed reversibility in 46% and MIBI in 22% (p < 0.001). TL detected reversibility in 84% of patients and MIBI in 48% (p = 0.007).

CONCLUSIONS

Although the two methods were similar for perfusion defects identification, the present study suggests that thallium-201 reinjection is superior to single-day rest-stress 99mTc-sestamibi for the detection of reversibility. Clinical relevance of these differences, as a marker of viability, requires further evaluation of these patients after successful revascularization.

[The determination of the mitral valve area after commissurotomy. A comparison of 2 echocardiographic methods]

OBJECTIVE

To compare the mitral valvular area obtained by two-dimensional echocardiography (2DMVA) to that obtained by Doppler through pressure half-time, (T1/2P) method (DMVA) in patients submitted to open or closed commissurotomy.

POPULATION

Data were obtained from 53 patients, 44 females and 9 males who ranged in age from 19 to 63 years (mean = 40.4 +/- 8) submitted to open commissurotomy (group A) or closed procedure (group F). The time from surgery to Echo ranged from 10 to 100 months (mean = 63 +/- 26). Ther were twenty one patients, in group A and 32 in group F.

METHODS

All the patients underwent two-dimensional echocardiography and continuous-wave doppler, guided by image and sound, so that the maximum velocity was located, using a Diasonics DRF 300 machine equipped with a combined echo-Doppler 3.5 mHz transducer. The mitral valve was visualized in short axis view the 2D mitral valve area was measured as the planimetered area along the inner border of the smallest orifice, while scanning through the short axis. Continuous-wave Doppler recordings were performed at 50 mm/s. The pressure half-time was measured as the interval between maximum velocity and maximum velocity/1.4. The valvular area (DMVA) was obtained by the expression 220/T1/2p. Maximum velocity (VMax) of mitral flux and the prevalence of significant mitral regurgitation (> = 2) were also compared in groups A and F. The relationship between 2DMVA and DMVA were compared by simple linear regression analysis and the other parameters by the t test and by chi-squared analysis.

RESULTS

2DMVA in the total patients was 2.26 +/- 0.59 and the DMVA 2.31 +/- 0.76 (NS). There were no significant difference between groups A e F concerning: VMax = 162.48 +/- 28.15 and 150.09 +/- 30.08, DMVA = 2.34 +/- 0.75 and 2.29 +/- 0.76 respectively, and mitral regurgitation = 2 patients in both groups. The correlation between the Doppler and the 2D obtained areas was good in group A r = 0.76 SEE there were no correlation between these values in group F r = 0.33.

CONCLUSIONS

We can conclude that the mitral valvular area obtained by two-dimensional echocardiography, correlates to the Doppler mitral valvular area in patients with prior open commissurotomy proving the complementary role of the two methods.

[Echo-Doppler in patients undergoing mitral commissurotomy. Comparison of open and closed commissurotomy]

OBJECTIVE

1. To evaluate with Echo-Doppler the medium/long term results of mitral commissurotomy. 2. To compare the results of open mitral commissurotomy to those of closed commissurotomy.

PATIENTS AND METHODS

The Echo 2D-Doppler study has been performed in 117 patients (104 females and 13 males), randomly selected among patients previously submitted to open (62 d.) or closed (55 d.) mitral commissurotomy, with greater than or equal to 12 months follow-up. Pulsed and continuous Doppler recordings were obtained in all 117 patients, and the following parameters were evaluated: Maximum Mitral Gradient (MG); mitral valvular area calculated by half-pressure time (MVA); presence of mitral regurgitation greater than or equal to grade 2 (MR); evaluation of systolic Pulmonary Artery pressure (PAP) by the gradient RV/RA + 14mmHg, in the patients with tricuspid insufficiency; acceleration time (ACT), ejection time (EJT) and the relation ACT/EJT in pulmonary artery. To compare the results of open commissurotomy, to those of closed commissurotomy, and in order to minimize the pre-operative differences between the patients submitted to each of these interventions, only the patients in the same NYHA functional class before surgery (class III), and in sinus rhythm have been selected. In this way two groups were compared: group A-24 patients with open commissurotomy and group F-37 patients with closed commissurotomy.

RESULTS

in the total of patients the results were: MG-9.8 +/- 4.2 mmHg; MVA-2.3 +/- 0.95 cm2; MR 16 pts. (13.7%); PAP obtained in 30 pts. (25.6%) -27.47 +/- 1.18 mmHg; the ACT, the EJT and the relation ACT/EJT in PA were respectively 115.63 +/- 34 ms, 309.9 +/- 38.5 ms, 0.37 +/- 0.1. The Doppler parameters obtained respectively in group A and in group F were: MG 8.96 +/- 4.5 mmHg and 10.38 +/- 3.82 mmHg (ns); MVA 2.62 +/- 1.01 cm2 and 2.08 +/- 0.84 cm2 (ns); MR 8.3% and 15.6% (ns) (Fig.3); the PAP have been calculated on 5(20.8%) patients in group A and on 10(27%) patients in group F and their respective values were 30.78 +/- 0.48 mmHg and 28.26 +/- 1.11 mmHg (ns); ACT 109.09 +/- 41.55 ms and 116.67 +/- 33.22 ms (ns); EJT 297.27 +/- 72.94 ms and 308.7 +/- 41.58 ms; ACT/EJT 0.35 +/- 0.12 and 0.38 +/- 0.10 (ns).

CONCLUSION

Both open and closed commissurotomy revealed to be good therapeutic alternatives to mitral stenosis with identical long term results as evaluated by Echo-Doppler. The results of percutaneous mitral valvuloplasty should be compared with these in the future.