Dipyridamole stress myocardial perfusion by computed tomography in patients with left bundle branch block

Cabeda, Estêvan Vieira; Falcão, Andréa Maria Gomes; Soares Jr., José; Rochitte, Carlos Eduardo; Nomura, César Higa; Ávila, Luiz Francisco Rodrigues; Parga, José Rodrigues

doi:10.5935/abc.20150117

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Original Articles • Arq. Bras. Cardiol. 105 (6) • Dec 2015 • https://doi.org/10.5935/abc.20150117 copy

Dipyridamole stress myocardial perfusion by computed tomography in patients with left bundle branch block

Authorship SCIMAGO INSTITUTIONS RANKINGS

Abstract

Background:

Functional tests have limited accuracy for identifying myocardial ischemia in patients with left bundle branch block (LBBB).

Objective:

To assess the diagnostic accuracy of dipyridamole-stress myocardial computed tomography perfusion (CTP) by 320-detector CT in patients with LBBB using invasive quantitative coronary angiography (QCA) (stenosis ≥ 70%) as reference; to investigate the advantage of adding CTP to coronary computed tomography angiography (CTA) and compare the results with those of single photon emission computed tomography (SPECT) myocardial perfusion scintigraphy.

Methods:

Thirty patients with LBBB who had undergone SPECT for the investigation of coronary artery disease were referred for stress tomography. Independent examiners performed per-patient and per-coronary territory assessments. All patients gave written informed consent to participate in the study that was approved by the institution’s ethics committee.

Results:

The patients’ mean age was 62 ± 10 years. The mean dose of radiation for the tomography protocol was 9.3 ± 4.6 mSv. With regard to CTP, the per-patient values for sensitivity, specificity, positive and negative predictive values, and accuracy were 86%, 81%, 80%, 87%, and 83%, respectively (p = 0.001). The per-territory values were 63%, 86%, 65%, 84%, and 79%, respectively (p < 0.001). In both analyses, the addition of CTP to CTA achieved higher diagnostic accuracy for detecting myocardial ischemia than SPECT (p < 0.001).

Conclusion:

The use of the stress tomography protocol is feasible and has good diagnostic accuracy for assessing myocardial ischemia in patients with LBBB.

Keywords:
Bundle-Branch Block; Myocardial Perfusion Imaging; Multidetector Computed Tomography; Coronary Angiography; Dipyridamole; Coronary Artery Disease

Modality	Gating	kV		mA
Modality	Gating	< 29 Kg/m²	> 29 Kg/m²	< 29 Kg/m²	> 29 Kg/m²
CACS	Prospective	120	120	150	300
Stress CTP	Prospective	100	120	580	450-580
CTA and rest CTP	Prospective^* * One retrospective exam was made due to the tachycardia at rest.	100	120	580	450-580

Effective radiation exposure (mSv)	Dados
Total Radiation dose of CT protocol	9.3 ± 4.6
CACS scan	0.8 ± 0.3
Stress scan	3.8 ± 3
Rest scan	3.7 ± 2
SPECT^* * Thallium-201 was used in two patients, with 99m TC-sestamibi being used in the remaining 28 patients.	14.6 ±4.4
Other parameters
Total Contrast material dose, (ml)	131 ± 10.3
CTA image quality (subjective analysis)	1.8 ± 0.9
Heart rate (beats/min)
Basal heart rate on CT room	71.1 ± 11.6
Stress scan heart rate	87.3 ± 12.2
Increase heart rate with dipyridamole^† † Mean value.	18%
Rest scan heart on CTA	62.7 ± 9

	Per-Patient Analysis ^‡ ‡ p < 0.05.				Per-Territory Analysis ^‡ ‡ p < 0.05.
	CTP	CTA	*SPECT^ * In SPECT per-patient analysis, the presence of fixed defect or/and ischemia was used.**	CTP + CTA	CTP	CTA	SPECT ^† † In SPECT per-territory analysis only ischemia was used.	CTP + CTA
Accuracy	83%	90%	63%	90%	79%	91%	69%	89%
Sensitivity	86%	86%	97%	93%	63%	85%	44%	85%
Specificity	81%	94%	32%	87%	86%	94%	79%	90%
PPV	80%	92%	56%	87%	65%	85%	48%	79%
NPV	87%	88%	92%	93%	84%	94%	77%	93%
A					B
CTP	QCA ≥ 70%				CTP	QCA ≥ 70%
CTP	-	+	Total		CTP	-	+	Total
-	13	2	15		-	54	10	64
+	3	12	15		+	9	17	26
Total	16	14	30		Total	63	27	90
p = 0.001					p < 0.001
A					B
SPECT	QCA ≥ 70%				SPECT	QCA ≥ 70%
SPECT	-	+	Total		SPECT	-	+	Total
-	5	0	0		-	50	15	65
+	11	14	25		+	13	12	25
Total	16	14	30		Total	63	27	90
p = 0.045					p < 0.021

C	Per-Patient Analysis			Per-Territory Analysis
C	CTP ^§ § p > 0.05. The others analysis p < 0.05.	CTA	SPECT ^§ § p > 0.05. The others analysis p < 0.05.	CTP	CTA	SPECT ^§ § p > 0.05. The others analysis p < 0.05.
Accuracy	70%	87%	63%	71%	84%	59%
Sensitivity	67%	89%	89%	50%	73%	36%
Specificity	75%	83%	25%	90%	94%	79%
PPV	80%	89%	64%	81%	91%	60%
NPV	60%	83%	60%	67%	80%	58%

Sociedade Brasileira de Cardiologia - SBC Avenida Marechal Câmara, 160, sala: 330, Centro, CEP: 20020-907, (21) 3478-2700 - Rio de Janeiro - RJ - Brazil, Fax: +55 21 3478-2770 - São Paulo - SP - Brazil
E-mail: revista@cardiol.br

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[1] Mailing Address: Estêvan Vieira Cabeda , Clínica Kozma. Rua Teixeira Soares, 793 - Centro, Postal Code 99010-080, Passo Fundo, RS – Brazil. E-mail: estevancabeda@cardiol.br, estevancabeda@gmail.com

Demographic data and Risc factor	Valores
Age (years), mean ± SD	62 ± 10
White Ethnicity, n (%)	19 (63%)
Woman, n (%)	18 (60%)
Hypertension, n (%)	21 (71%)
Smoker, n (%)	3 (10%)
Diabetes, n (%)	14 (46%)
Dyslipidemia, n (%)	28 (93%)
Familiar history of IHD, n (%)	12 (40%)
Overweight (BMI > 25 kg/m²), n (%)	17 (56%)
Obesity (BMI > 30 kg/m²), n (%)	9 (30%)
Dyspneia, n (%)	18 (60%)
Chest pain, n (%)	18 (60%)
Ejection fraction, mean ± SD	42.4 ± 17
Biomaker or lipid level (mg/dl)
Total cholesterol, mean ± SD	192 ± 57
HDL cholesterol, mean ± SD	45 ± 10
LDL cholesterol, mean ± SD	119 ± 41
Serum tryglyceride, mean ± SD	135 ± 95