Association between Hemogram Parameters and Coronary Collateral Development in Subjects with Non-ST-Elevation Myocardial Infarction

SUMMARY OBJECTIVE Coronary collateral development (CCD) predicts the severity of coronary heart disease. Hemogram parameters, such as mean platelet volume (MPV), eosinophil, red cell distribution width, and platelet distribution width (PDW), are supposed novel inflammatory markers. We aimed to compare hemogram parameter values in patients presenting with non-ST-elevation myocardial infarction (NSTEMI) with adequate or inadequate CCD. METHODS A total of 177 patients with NSTEMI undergoing coronary arteriography were enrolled and divided into two groups based on the development of CCD: one group with adequate CCD (n=88) and the other with impaired CCD (n=89). RESULTS Baseline demographics and clinical risk factors were similar between the groups. Hemogram parameters were not significantly different between the two groups. However, compared to the inadequate CCD group, the median PDW was significantly higher in the adequate CCD group, 17.6 (1.4) vs. 17.8 (1.6) p=0.004. In a multivariate analysis, PDW (p=0.001, 95% CI for OR: 0.489(0,319-0,750) was found to be significantly different in the adequate CCD group compared to the inadequate CCD group. Pearson's correlation analysis revealed that PDW was significantly correlated with the Rentrop score (r=0.26, p<0.001). CONCLUSIONS We suggest that since PDW is an index that is inexpensive and easy to assess, it could serve as a marker of CCD in patients with NSTEMI.

RESUMO OBJETIVO O desenvolvimento colateral coronariano (CCD) prediz a gravidade da doença coronariana. Parâmetros de hemograma como volume plaquetário médio (VPM), eosinófilo, largura de distribuição de glóbulos vermelhos e largura de distribuição de plaquetas (PDW) são supostos novos marcadores inflamatórios. Nosso objetivo foi comparar os valores do parâmetro hemograma em pacientes com infarto do miocárdio sem supradesnivelamento do segmento ST (IAMSSST) com DCC adequado ou inadequado. MÉTODOS Um total de 177 pacientes com NSTEMI submetidos à arteriografia coronariana foram incluídos e divididos, com base no desenvolvimento de CCD, em dois grupos: grupo com CCD adequado (n = 88) e grupo com CCD alterado (n = 89). RESULTADOS Os dados demográficos e os fatores de risco clínicos basais foram semelhantes entre os grupos. Os parâmetros do hemograma não foram significativamente diferentes entre os dois grupos. Mas, em comparação com a mediana inadequada do grupo CCD, o PDW foi significativamente maior em CCD adequado de 17,6 (1,4) vs. 17,8 (1,6) p = 0,004. Na análise multivariada, PDW (p = 0,001, IC 95% para OR: 0,489 (0,319-0,750) foi significativamente diferente no grupo CCD adequado em comparação com o grupo CCD inadequado. A análise de correlação de Pearson revelou que PDW foi significativamente correlacionado com escore de aluguel (r = 0,26, p <0,001). CONCLUSÃO Sugerimos que, uma vez que a PDW é um índice barato e de fácil avaliação, pode servir como um marcador de DCC em pacientes com IAMSSST.

Coronary perfusion pressure during antegrade cardioplegia in on-pump CABG patients

Abstract Objective: The aim of this study was to investigate whether aortic tension estimated by palpation and cardioplegia infusion line pressure provide results equivalent to those obtained with direct aortic intraluminal pressure measurement. Methods: Sixty consecutive patients who underwent coronary artery bypass graft surgeries with extracorporeal circulation were analyzed. Sanguineous cardioplegic solution in a ratio of 4:1 was administered using a triple lumen antegrade cannula. After crossclamping, cardioplegia was infused and aortic root pressure was recorded by surgeon (A) considering the aortic tension he felt in his fingertips. At the same time, another surgeon (B) recorded his results for the same measurement. Concomitantly, the anesthesiologist recorded intraluminal pressure in the aortic root and the perfusionist recorded delta pressure in cardioplegia infusion line. None of the participants involved in these measurements was allowed to be informed about the values provided by the other examiners. Results: The Bland-Altman test showed that a considerable variation between aortic wall tension was found as measured by palpation and by intraluminal pressure, with a bias of -9.911±18.75% (95% limits of agreement: -46.7 to 26.9). No strong correlation was observed between intraluminal pressure and cardioplegia line pressure (Spearman's r=0.61, 95% confidence interval 0.5-0.7; P<0.0001). Conclusion: These findings reinforce that cardioplegia infusion should be controlled by measuring intraluminal pressure, and that palpation and cardioplegia line pressure are inaccurate methods, the latter should always be used to complement intraluminal measurement to ensure greater safety in handling the cardioplegia circuit.

Which Coronary Lesions Are More Prone to Cause Acute Myocardial Infarction? / Quais Lesões Coronarianas São Mais Propensas a Causar Infarto Agudo do Miocárdio?

Abstract Background: According to common belief, most myocardial infarctions (MIs) are due to the rupture of nonsevere, vulnerable plaques with < 70% obstruction. Data from recent trials challenge this belief, suggesting that the risk of coronary occlusion is, in fact, much higher after severe stenosis. The aim of this study was to investigate whether or not acute ST-elevation MIs result from high-grade stenoses by evaluating the presence of coronary collateral circulation (CCC). Methods: We retrospectively included 207 consecutive patients who had undergone primary percutaneous coronary intervention for acute ST-elevation MI. Collateral blood flow distal to the culprit lesion was assessed by two investigators using the Rentrop scoring system. Results: Out of the 207 patients included in the study, 153 (73.9%) had coronary collateral vessels (Rentrop 1-3). The Rentrop scores were 0, 1, 2, and 3 in 54 (26.1%), 50 (24.2%), 51 (24.6%), and 52 (25.1%) patients, respectively. Triglycerides, mean platelet volume (MPV), white cell (WBC) count, and neutrophil count were significantly lower in the group with good collateral vessels (p = 0.013, p = 0.002, p = 0.003, and p = 0.021, respectively). Conclusion: More than 70% of the patients with acute MI had CCC with Rentrop scores of 1-3 during primary coronary angiography. This shows that most cases of acute MI in our study originated from underlying high-grade stenoses, challenging the common believe. Higher serum triglycerides levels, greater MPV, and increased WBC and neutrophil counts were independently associated with impaired development of collateral vessels.

Resumo Fundamento: Há uma crença geral de que a maioria dos infartos agudos do miocárdio (IAM) ocorrem devido à ruptura de placas vulneráveis, não graves, com obstrução < 70%. Dados de ensaios recentes desafiam esta crença, sugerindo que o risco de oclusão coronariana é, na realidade, muito maior após estenose grave. O objetivo deste estudo foi investigar se a presença ou não de IAM com supradesnível do segmento ST resulta de estenoses de alto grau através da avaliação da presença de circulação colateral coronariana (CCC). Métodos: Nós incluímos retrospectivamente 207 pacientes consecutivos submetidos à intervenção coronariana percutânea primária devido à ocorrência de IAM com supradesnível do segmento ST. O fluxo sanguíneo colateral distal à lesão culpada foi avaliado por dois investigadores com utilização do sistema de escores de Rentrop. Resultados: Dos 207 pacientes incluídos no estudo, 153 (73,9%) apresentavam vasos coronarianos colaterais (Rentrop 1-3). Os escores Rentrop foram de 0, 1, 2 e 3 em 54 (26,1%), 50 (24,2%), 51 (24,6%) e 52 (25,1%) pacientes, respectivamente. Triglicérides, volume plaquetário médio (VPM), contagem de células brancas (CCB) e contagem de neutrófilos estiveram significativamente mais baixos no grupo com bons vasos colaterais (p = 0,013, p = 0,002, p = 0,003 e p = 0,021, respectivamente). Conclusão: Mais de 70% dos pacientes com IAM apresentaram CCC com escores de Rentrop de 1-3 durante angiografia coronariana primária. Isto demonstra que a maioria dos casos de IAM em nosso estudo originou a partir de estenoses subjacentes de alto grau, contrariamente à sabedoria comum. Níveis séricos mais elevados de triglicérides, maior VPM e elevação na CCB e na contagem de neutrófilos estiveram independentemente associados com comprometimento no desenvolvimento de vasos colaterais.

Increased neutrophil-to-lymphocyte ratio predicts persistent coronary no-flow after wire insertion in patients with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention

OBJECTIVES: Acute ST-segment elevation myocardial infarction patients presenting persistent no-flow after wire insertion have a lower survival rate despite successful mechanical intervention. The neutrophil-to-lymphocyte ratio has been associated with increased mortality and worse clinical outcomes in ST-segment elevation myocardial infarction. We hypothesized that an elevated neutrophil-to-lymphocyte ratio would also be associated with a persistent Thrombolysis In Myocardial Infarction flow grade of 0 after wire insertion in patients undergoing primary percutaneous coronary intervention. METHODS: A total of 644 patients with ST-segment elevation myocardial infarction who underwent primary percutaneous coronary intervention within 12 hours of symptom onset were included in our study. Blood samples were drawn immediately upon hospital admission. The patients were divided into 3 groups according to their Thrombolysis In Myocardial Infarction flow grade: Thrombolysis In Myocardial Infarction flow grade 0 after wire insertion, Thrombolysis In Myocardial Infarction flow grade 1-3 after wire insertion and Thrombolysis In Myocardial Infarction flow grade 1-3 at baseline. RESULTS: The neutrophil-to-lymphocyte ratio was significantly higher in the group with Thrombolysis In Myocardial Infarction flow grade 0 after wire insertion compared with the group with Thrombolysis In Myocardial Infarction flow grade 1-3 after wire insertion and the group with Thrombolysis In Myocardial Infarction flow grade 1-3 at baseline. The group with Thrombolysis In Myocardial Infarction flow grade 0 after wire insertion also had a significantly higher in-hospital mortality rate. Persistent coronary no-flow after wire insertion was independently associated with the neutrophil-to-lymphocyte ratio. CONCLUSIONS: An increased neutrophil-to-lymphocyte ratio on admission is significantly associated with persistent coronary no-flow after wire insertion in patients with ST-segment ...

Reserva de Velocidade de Fluxo Coronariano durante o Ecocardiograma sob Estresse com Dobutamina / Coronary Flow Velocity Reserve during Dobutamine Stress Echocardiography

Fundamento: A reserva de velocidade de fluxo coronariano (RVFC) ≥ 2 é adequada para inferir bom prognóstico ou ausência de coronariopatia importante. Objetivo: Identificar parâmetros relevantes na obtenção da RVFC (adequada ou inadequada) na descendente anterior (ADA), durante o ecocardiograma sob estresse com dobutamina (EED). Métodos: Avaliação de 100 pacientes encaminhados para pesquisa de isquemia miocárdica através do EED, orientados para suspender o betabloqueador 72 horas antes do exame. Calculou-se a RVFC pela divisão do pico de velocidade (cm/s) diastólica (PVD) verificado no EED (PVD-EED) pelo de repouso (PVD-REP). No grupo I, a RVFC < 2 e no grupo II a RVFC ≥ 2. Foram utilizados o teste t de Student e o exato de Fisher. Significância estatística quando p < 0,05. Resultados: Em repouso, o tempo (segundos) para obter o Doppler na ADA nos grupos I e II não diferiu (53 ± 31 vs. 45 ± 32; p = 0,23). No EED, registrou-se a ADA em 92 pacientes. O grupo I evidenciou pacientes mais velhos (65,9 ± 9,3 vs. 61,2 ± 10,8 anos; p = 0,04), menor fração de ejeção (61 ± 10 vs. 66 ± 6%; p = 0,005), maior PVD-REP (36,81 ± 08 vs. 25,63 ± 06 cm/s; p < 0,0001) e menor RVFC (1,67 ± 0,24 vs. 2,53 ± 0,57; p < 0,0001), entretanto o PVD-EED não diferiu (61,40 ± 16 vs. 64,23 ± 16 cm/s; p = 0,42). A suspensão do betabloqueador associou-se à chance 4 vezes maior de ocorrer RVFC < 2 (OR = 4; 95% IC [1,171 - 13,63], p = 0,027). Conclusão: O PVD-REP foi o principal parâmetro para determinar uma RVFC adequada. A suspensão do betabloqueador associou-se significativamente com RVFC inadequada. A elevada exequibilidade e o tempo para registro da ADA favorecem a utilização dessa metodologia. .

Background: A coronary flow velocity reserve (CFVR) ≥ 2 is adequate to infer a favorable prognosis or the absence of significant coronary artery disease. Objective: To identify parameters which are relevant to obtain CFVR (adequate or inadequate) in the left anterior descending coronary artery (LAD) during dobutamine stress echocardiography (DSE). Methods: 100 patients referred for detection of myocardial ischemia by DSE were evaluated; they were instructed to discontinue the use of β-blockers 72 hours prior to the test. CFVR was calculated as a ratio of the diastolic peak velocity (cm/s) (DPV) on DSE (DPV-DSE) to baseline DPV at rest (DPV-Rest). In group I, CFVR was < 2 and, in group II, CFVR was ≥ 2. The Fisher's exact test and Student's t test were used for the statistical analyses. P values < 0.05 were considered statistically significant. Results: At rest, the time (in seconds) to obtain Doppler in LAD in groups I and II was not different (53±31 vs. 45±32; p=0.23). During DSE, LAD was recorded in 92 patients. Group I patients were older (65.9±9.3 vs. 61.2±10.8 years; p=0.04), had lower ejection fraction (61±10 vs. 66±6%; p=0.005), higher DPV-Rest (36.81±08 vs. 25.63 ± 06cm/s; p<0.0001) and lower CFVR (1.67 ± 0.24 vs. 2.53 ± 0.57; p<0.0001), but no difference was observed regarding DPVDSE (61.40±16 vs. 64.23±16cm/s; p=0.42). β-blocker discontinuation was associated with a 4-fold higher chance of a CFVR < 2 (OR= 4; 95% CI [1.171-13.63], p=0.027). Conclusion: DPV-Rest was the main parameter to determine an adequate CFVR. β-blocker discontinuation was significantly associated with inadequate CFVR. The high feasibility and the time to record the LAD corroborate the use of this methodology. .

Medida do fluxo intraoperatório com fluxômetro TTFM nos enxertos coronários: resultados de amostra nacional / Intraoperative coronary grafts flow measurement using the TTFM flowmeter: results from a domestic sample

OBJETIVO: Avaliar a perviedade dos enxertos no intraoperatório e identificar enxertos com risco de oclusão precoce. MÉTODOS: Cinquenta e quatro pacientes foram submetidos à revascularização do miocárdio e foi utilizado o fluxômetro (Medtronic Medi-Stim) que utiliza o método de tempo de trânsito (TTFM) para avaliação do fluxo nos enxertos. Três pacientes tinham lesão de tronco de artéria coronária esquerda e 48 apresentavam função ventricular normal ou pouco comprometida. RESULTADOS: A mortalidade hospitalar foi de dois (3,7%) pacientes, um por trombose mesentérica e outro por choque cardiogênico. Dezessete (31,4%) pacientes foram operados sem circulação extracorpórea (CEC). O fluxo no enxerto arterial variou de 8 a 106 ml/min, com média de 31,14 ml/min, e nos enxertos venosos de 9 a 149 ml/min, com média de 50,42 ml/min. CONCLUSÃO: O fluxômetro representa maior segurança para o cirurgião e para o paciente. Até mesmo sob o aspecto legal essa documentação dos enxertos pérvios evitará questionamentos futuros.

OBJECTIVE: To evaluate intraoperative graft patency and identify grafts under risk of early occlusion. METHODS: Fifty four patients were submitted to coronary artery bypass surgery and the graft flow was assessed by the Flowmeter (Medtronic Medistim), which utilizes the TTFM method. Three patients had left main disease and 48 had normal or mildly reduced left ventricular function. RESULTS: In hospital mortality was 3.7% (two patients), one for mesenteric thrombosis and one due to cardiogenic chock. Seventeen patients (34%) were submitted to off pump CABG. Arterial Graft flow measures ranged from 8 to 106 ml/min (average 31.14 ml/min), and venous grafts flow ranged from 9 to 149 ml/min (average 50.42 ml/min). CONCLUSION: Flowmeter use represents higher safety both for patients and surgeons. Even under legal aspects, the documentation provided by the device can avoid future questionings.

Absence of arteriosclerosis in intramyocardial coronary arteries: a mystery to be solved? / Ausência de arteriosclerose na porção intramiocárdica das artérias coronárias: um mistério a ser resolvido?

Several studies show that portions of intramyocardial coronary arteries are spared of arteriosclerosis, involving morphological, embryological, biochemical and pathophysiological aspects. Endothelial function is significantly affected in the segment of transition, as estimated by the vasoactive response to Ach. These findings suggest that myocardial bridge can provide protection against arteriosclerosis by counteracting the negative effects of endothelial dysfunction. The intramyocardial portion's protection phenomenon deserves further scientific research on all research fronts. Improved morphological, biomechanical and especially physiological and embryological knowledge may be the key to a future window of opportunity for chronic arterial disease therapy and prevention. In addition, this review discusses possible therapeutic approaches for symptomatic coronary ischemia caused by myocardial bridges.

Diversos estudos demonstram que as porções intramiocárdicas das artérias coronárias são poupadas da arteriosclerose, envolvendo aspectos morfológicos, embriológicos, biomecânicos e aspectos fisiopatológicos. A função endotelial é significativamente afetada no segmento de transição, tal como estimado pela resposta vasoativa para acetilcolina (Ach). Esses achados sugerem que ponte miocárdica pode fornecer proteção contra a arteriosclerose, por contrariar os efeitos negativos da disfunção endotelial. O fenômeno dessa proteção da porção intramiocárdica merece maior investigação científica em todas as frentes de pesquisa. Maiores conhecimentos sobre os aspectos morfológicos, biomecânicos e, principalmente, fisiológicos e embriológicos podem ser a chave para uma futura janela de oportunidades de terapia e prevenção da doença arterial crônica. Nessa revisão, discutem-se, também, possíveis abordagens terapêuticas para fenômenos coronarianos isquêmicos causados por pontes miocárdicas.

Miocárdio viável pela tomografia computadorizada com Tc-99m (MIBI) sensibilizada por nitroglicerina endovenosa / Viable myocardium scintigraphy with intravenous nitroglycerine by computed tomography with Tc-99m (MIBI)

FUNDAMENTO: A seleção de pacientes com doença coronariana crônica para recanalização baseia-se na detecção do miocárdio comprometido, potencialmente viável. OBJETIVO: Avaliar o miocárdio isquêmico, potencialmente viável pelo SPECT com MIBI sensibilizado por nitroglicerina em dose máxima tolerada. MÉTODOS: Investigamos de forma prospectiva, de abril de 2004 a novembro de 2005, pela tomografia computadorizada por emissão de fóton único SPECT com Tc-99m (MIBI), 40 pacientes (média etária 62 ± 8,9 anos, 30 homens) com obstrtução coronariana demonstrada angiograficamente, e a cintilografia miocárdica foi realizada em repouso e com nitroglicerina endovenosa (EV), iniciando com a dose (1 µg/kg/min) e incremento a cada minuto, até a queda da pressão arterial sistólica em 20 mmHg. A redução da perfusão dos segmentos foi classificada em moderada e severa, e comparada depois da nitroglicerina. Analisamos as variáveis angiográficas, hemodinâmicas e de perfusão miocárdica. RESULTADOS: Analisamos 680 segmentos miocárdicos em repouso: 538 com distribuição homogênea e 142 com hipoperfusão (54 com redução moderada e 88 severa). Depois da nitroglicerina, ocorreu aumento da perfusão em 19 (47,5 por cento) de 40 pacientes. Tornaram-se viáveis 55 de 142 segmentos: 33 (61,1 por cento) com redução moderada e 22 (25 por cento) com redução severa, ambos apresentaram aumento significativo da distribuição do radiofármaco (p < 0,001, qui-quadrado). CONCULSÃO: Dos componentes com Tc-99m, está incluído o Tc-99m-2-methoxy-isobutil-isonitrila (MIBI) que, utilizado com dose otimizada de nitroglicerina EV, pode aumentar a captação do radiofármaco em áreas com hipoperfusão moderada e severa. Os resultados deste estudo sugerem aumento da sensibilidade do Tc-99m (MIBI) pela nitroglicerina para detecção de miocárdio viável.

BACKGROUND: The selection of patients with chronic coronary disease for recanalization is based on the detection of the affected myocardium that is potentially viable. OBJECTIVE: To evaluate the potentially viable ischemic myocardium through single photon emission computed tomography (SPECT) with MIBI after a maximum tolerated dose of I.V. nitroglycerin. METHODS: We prospectively investigated by SPECT with Tc-99m (MIBI), from April 2004 to November 2005, 40 patients (mean age: 62 ± 8.9 yrs, 30 men) with coronary obstruction demonstrated angiographically; the myocardium scintigraphy was carried out at rest and after intravenous (I.V.) nitroglycerin, which was started at a dose of 1 µg/kg/min and increased every minute until the systolic blood pressure decreased by 20 mmHg. The decrease in the perfusion of the segments was classified as moderate or severe and compared after the nitroglycerin. The angiographic, hemodynamic and myocardial perfusion variables were analyzed. RESULTS: We analyzed 680 myocardial segments at rest: 538 with a homogenous distribution and 142 with hypoperfusion (54 with moderate and 88 with severe decrease). After the nitroglycerin, there was an increase in the perfusion in 19 (47.5 percent) of 40 patients and 55 of 142 segments became viable: 33 (61.1 percent) with moderate and 22 (25 percent) with severe decrease; both presented a significant increase in the radiotracer distribution (p < 0.001, Chi-square). CONCLUSION: One of the components with Tc-99m is Tc-99m 2-methoxy-isobutyl-isonitrile (MIBI), which, when used with an optimized dose of I.V. nitroglycerin, can increase the radiotracer uptake in areas with moderate and severe hypoperfusion. The results of the present study suggest the increase in the Tc-99m (MIBI) sensitivity by nitroglycerin for the detection of viable myocardium.

Tônus e diâmetro arterial coronário não se correlacionam com o grau de denervação autonômica em pacientes com cardiopatia chagásica crônica / Coronary artery diameter and baseline tonus do not correlate with degree of cardiac parasympathetic impairment in patients with chronic chagas cardiomypathy

Introdução: Portadores de cardiopatia chagásica crônica (CCC) apresentam precoce e intensa disautonomia, postulando-se potenciais anormalidades vasomotoras coronárias e conseqüente isquemia e fibrose miocárdica. Esta investigação correlacionou o grau de denervação parassimpática cardíaca com o diâmetro e o tônus arterial coronário. Método: Em 18 pacientes com CCC (55 ± 9 anos, 8 do gênero masculino) e 23 voluntários normais (37 ± 11 anos, 16 do gênero masculino), avaliou-se a sensibilidade barorreflexa (SBR) com monitoração contínua da pressão arterial (PA) e indução de aumentos transitórios da PA por administração endovenosa de fenilefrina (50 µg a 150 µg). Cateterismo cardíaco com cinecoronariografia basal e 5 minutos após 5 mg de dinitrato de isossorbida (DNIS) foi realizado em pacientes chagásicos. Análise quantitativa do diâmetro arterial coronário foi realizada off-line nas duas condições. O tônus basal arterial coronário foi estimado pelo aumento porcentual do diâmetro após DNIS. A fração de ejeção do ventrículo esquerdo (FEVE) foi calculada pelo método de Dodge biplanar na ventriculografia de contraste, usando-se ecocardiografia bidimensional para o diâmetro diastólico (DDVE) e estimativa da massa do ventrículo esquerdo. Resultados: Verificou-se acentuada redução da SBR (4,1 ± 1,7 ms/mmHg) na CCC comparativamente aos controles (15,0 ± 1,5 ms/mmHg) (p < 0,001). O diâmetro coronário médio foi de 2,2 ± 0,3 mm, correlacionando-se significativamente com variáveis expressando remodelamento cardíaco: FEVE (p = 0,017, R = 0,554), DDVE (p = 0,0036, R = 0,648) e massa VE (p = 0,022, R = 0,534). Não foi observada correlação significante entre diâmetro coronário e SBR (p = 0,457, R = 0,187). O tônus arterial coronário basal foi de 13 ± 17%, sem correlação com qualquer variável, incluindo o diâmetro coronário (p = 0,386, R = 0,218) e a SBR (p = 0,822, R = 0,057). Conclusões: A denervação parassimpática não parece influenciar o diâmetro e o tônus arterial coronário basal na CCC.

Background: Chronic Chagas Cardiomyopathy (CCC) induces early severe cardiac dysautonomia, potentially causing derangements in the regulation of coronary vasomotion and leading to myocardial ischemia and fibrosis. We assessed the correlation between dysautonomia severity and coronary artery diameter and tonus. Methods: Eighteen patients with CCC (55±9 yrs, 8 males) and 23 normal volunteers (37±11 yrs, 16 males) were investigated. Both groups underwent evaluation of baroreflex sensitivity (BRS) by means of invasive arterial pressure (AP) monitoring and transient increases of AP induced by intravenous phenilephrinefrin injections (50-150µg). Patients with CCC had cardiac catheterization and coronary angiography at baseline and 5 min. after administration of 5mg of isosorbide-dinitrate (ISDN). Quantitative coronary analysis was performed off-line for both conditions (baseline and post-ISDN). Baseline coronary artery tonus was calculated by the percent diameter increase after ISDN. LVEF was calculated by Dodge biplane method from contrast ventriculography and 2D-echocardiogram was used for the measurement of LV diastolic diameter and mass. Results: CCC patients showed severe reduction of the BRS (4.1 ± 1.7 ms/mmHg) as compared to controls (15.0 ± 1.5 ms/mmHg), p < 0.001. Mean coronary artery diameter was 2.2 ± 0.3 mm, and was significantly correlated with parameters of LV remodeling: LEFF (p = 0.017, R = 0.554), LVDD (p = 0.0036, R = 0.648) and LV mass (p = 0.022, R = 0.534). No significant correlation occurred between coronary diameter and the BRS (p = 0.457, R = 0.187). Baseline coronary tonus was 13 ± 17%, without correlation with any variables, including coronary diameter (p = 0.386, R = 0.218) and BRS (p = 0.822, R = 0.057). Conclusions: Cardiac parasympathetic impairment does not seem to determine coronary artery diameter and tonus in patients with CCC.

Studies of the coronary circulation in Chagas' heart disease

Pathogenesis of chronic Chagas' heart disease may include various disturbances in the coronary circulation, that could be responsible for the myocardial lesions seen in human hearts and in experimental models of the disease. In this paper we critically reviewed the anatomical and functional abnormalities described in chronic chagasic patients, pertaining to the so-called vascular pathogenetic theory of Chagas' disease. The epicardial coronary arteries are usually tree of significant obstructive disease in nonselected groups of chagasic patients examined at autopsy or by coronary angiography. However, chagasic patients who were studied after an episode of acute myocardial infarction, show the same patterns of atherosclerotic coronary artery disease seen in the general nonchagasic population. Studies of chagasic patients with angiographically normal coronary arteries, by several scintigraphy methods, revealed myocardial perfusion abnormalities which may be caused by the microcirculatory derangements described in animals experimentally infected with the T. cruzi. Since hypoperfusion has been detected in regions with normal or mildly impaired wall motion, it is likely that the microvascular disturbances precede and may be a causative mechanism for the subsequent myocardial damage. We speculate that hibernating ventricular areas may occur in chagasic patients, on the basis of the evidence gathered from these studies. Recent investigations of chronic patients with Chagas' disease and chest pain showed attenuation of the vasomotor responses to physiological and pharmacological stimuli, in the epicardial coronary arteries.