Spontaneous Coronary Artery Dissection: Aggressive vs. Conservative Therapy
- Volume 22 - Issue 5 - May, 2010
- Posted on: 5/6/10
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ABSTRACT: Background. Spontaneous coronary artery dissection (SCAD) is a rare condition that commonly presents as an acute coronary event in the younger population, especially in females of childbearing age. Generally, there is no consensus on the etiology, prognosis, and treatment of SCAD. Methods. The Medline database was searched for “spontaneous coronary artery dissection” between 1931 and 2008. A total of 440 cases of SCAD were identified. Demographic data were analyzed with either the Student’s t-test or the chi-square test for categorical and nominal variables, respectively. Kaplan-Meier outcome analysis was used to assess the outcome of a given treatment for all patients after 1990. Result. SCAD was found more commonly in females with 308 (70%) cases. Pregnancy was associated with SCAD in 80 (26.1%) cases. Among pregnant patients, 67 (83.8%) developed SCAD in the postpartum period and 13 (16.2%) patients in the prepartum period. Analysis of treatment modalities showed that 21.2% of the patients who were conservatively managed after the initial diagnosis eventually required surgical or catheter-based intervention compared to 2.5% of patients who were initially treated with an aggressive strategy. Kaplan-Meier analysis showed that patients with an isolated single lesion in left or right coronary artery had a statistically significant better outcome when treated with an early aggressive strategy, including coronary artery bypass grafting (CABG) or stent placement as compared to a conservative strategy (p = 0.023, p = 0.006, respectively). Conclusion. Early intervention with either CABG or percutaneous coronary intervention following the diagnosis of SCAD leads to a better outcome and less need for further intervention.
J INVASIVE CARDIOL 2010;22:222–228
Spontaneous coronary artery dissection (SCAD) is a separation of the coronary artery wall layers by hemorrhage with or without an associated intimal tear.1 It is a rare condition that mainly presents in the younger female population,2,3 and typically manifests as an acute coronary event. The first known case was documented in an autopsy performed on a 42-year-old female in 1931. 4 Since then, a number of anecdotal references have been made in the literature.
Previously, diagnosis was mainly made by postmortem examination until the advent of advanced cardiac imaging. Now, more cases of SCAD are being diagnosed with the widespread use of coronary angiography. SCAD can involve both the left and right coronary arterial system. The treatment modalities consist of conservative medical or aggressive management with percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery (CABG). Currently, there are no outcome studies or treatment guidelines for SCAD. The purpose of this study is to compare the effectiveness of various treatment modalities on the outcome of SCAD.
Material and Methods
We searched the Medline database using the key words “spontaneous coronary dissection,” and “primary and idiopathic coronary dissection” between 1931 and 2008. A total of 381 articles with a total of 485 published case reports, 7 review articles5–10,12 and a registry on SCAD11 were found. Forty-five cases, which were reported to be iatrogenic, were excluded. Forty-eight articles in languages other than English were found; however, 34 articles or abstracts contained sufficient data to be included in this analysis. A total of 440 cases with an acceptable pool of information were analyzed in this review.
Statistical analysis. All the data were summarized according to the cases observed in the literature. Demographic data were analyzed using either the Student’s t-test or the chi-square test for categorical and nominal variables, respectively. All statistical values were significant at a p-value < 0.05.
Kaplan-Meier outcome analysis was used to assess the outcome of a given treatment according to the anatomical site of the lesions for all patients after 1990. The primary endpoint for the analysis was a cardiac event which was defined as death, MI, angina or angina-equivalent requiring hospital admission after the diagnosis of SCAD. The cases in the review were followed for varying lengths of time. In order to homogenize the study population, it was truncated at 400 days from the first presentation. To determine the difference in the outcome based on the location of lesions, a separate analysis was performed on isolated single lesions in the left, right and combined left and right coronary arteries. A log rank test for each variable was computed to give the p-value. Statistical analysis was done using SPSS version 17.0 software (SPSS, Inc., Chicago, Illinois).
Baseline characteristics. We found a total of 440 patients with SCAD in the literature. We categorized the data based on gender and found that SCAD was more common in females, with 307 (70%) reported cases versus 133 (30.2%) for males. The mean age of the study population was 42.6 years (males: 45.4 ± 14.4 years, females: 41 ± 10.6 years), with a range of 17–82 years. Among female patients, 18 (5.8%) cases were associated with oral contraceptive (OCP) use and 12 (3.9%) cases occurred during activities which involved heavy exertion. Pregnancy was associated with coronary dissection in 80 (26%) cases. Among them, 67 (83.8%) events occurred in the postpartum period and 13 (16.2%) events before delivery (p = 0.001). Among postpartum patients, 47 (70.1%) cases occurred within 2 weeks following delivery. SCAD was more frequently encountered in males during activities which involved heavy exertion (n = 20 [15.3%]) (Table 1).
Presentation and anatomy of lesions. Out of the 440 cases of SCAD, 95 (21.5%) were diagnosed during postmortem examination. The diagnosis of SCAD in the remaining 345 (78.5%) cases was made mainly by coronary angiograms, less frequently by cardiac computed tomography (CCT) and rarely by cardiac magnetic resonance imaging. On reviewing histological examination of the postmortem cases, eosinophilic infiltration was the most frequent abnormality found in 23 (21.7%) cases (Figure 1).
Analysis of the 95 autopsy cases revealed that eosinophilic infiltration was present in 31.8% of pregnant patients (n = 7/22), whereas, in the absence of pregnancy it was seen in 32.6 % (n = 24/73) of cases (p = 0.537). Further, analysis of the autopsy cases showed, that cystic medial necrosis (CMN) was present in 31.8% (n = 7/22) of pregnant patients, whereas, in the absence of pregnancy, it was detected in 30.13% (n = 22/73) of cases (p = 0.440).
Among the 440 patients presenting with SCAD, chest pain was the most frequent symptom and occurred in 339 (77%) patients (Figure 2). Only 322 patients had electrocardiographic examination at the time of diagnosis. Among them, ST-segment elevation was present in 209 (64.9%). Overall, 602 lesions were reported in 440 patients. Dissection was found most frequently in the left anterior descending artery (LAD) (48%) (Figure 3).
The coronary artery lesions were classified based on the number and anatomical location. Isolated single-vessel dissection was 2.8 times more common than multivessel dissection (324 [73.6%] patients vs. 116 [26.4%] patients; p = 0.001). Isolated single lesions were found more often among males than among females (108 [81.2%] vs. 216 [70.4%]; p = 0.017). Isolated single lesions were found more often among males than among females (108 [81.2%] vs. 216 [70.4%]; p = 0.017). Isolated LAD, right coronary artery (RCA), left main coronary (LMC) artery and left circumflex artery (LCX) dissections were found in 178 (40.5%), 96 (21.9%), 27 (6.1%) and 23 (5.2%) patients, respectively.
Dissection involving 2 coronary vessels was reported in 71 (16.1%) cases of the entire study population (54 females and 17 males). Dissection involving more than 2 coronary vessels was found in 45 (10.2%) cases among all study patients, and was more common in females (38 [12.3%] vs. 7 [5.3%]; p = 0.026) (Table 2, Figure 4). Dissection involving 3 coronary vessels was found in 44 (10%) cases among all study patients, and was more common in females (37 [12.1%] vs. 7 [5.3%]; p = 0.029) (Table 2, Figure 4). Five patients developed new dissection in the coronary arteries which did not show dissection in the initial angiography, of which all 5 patients were conservatively treated. 13–17
Of the 345 patients with SCAD who were initially diagnosed by coronary angiography or cardiac CT, 121 (35.1%) underwent a subsequent procedure. Indications for a subsequent procedure included chest pain in 37 (30.6%) subjects, cardiogenic shock in 5 (4.1%) and coronary angiography was performed as an elective follow up in the absence of any symptoms in 79 (65.3%) patients. SCAD lesions persisted or worsened in 67.5% of the patients who were treated conservatively and underwent repeat coronary angiography, compared to 25.9% patients who were initially treated with CABG or stenting (p = 0.001).
Management strategy. Our analysis showed that common treatment modalities used to manage SCAD were conservative management and catheter-based or surgical intervention. All of the above treatment modalities were not commonly available in the years prior to 1990. Out of 344 cases of SCAD diagnosed after 1990, 30 (8.7%) patients died prior to hospitalization. Of the remaining 314 patients, aggressive management was the first treatment modality in 158 (CABG #91, PCI #67), and conservative management was applied to 156 patients.
Among the 314 patients, 110 (35.5%) underwent subsequent coronary angiography. Eighty-three (75.5%) of these patients, were initially managed conservatively compared to 12 (10.9%) subjects who underwent CABG and 15 (13.6%) who were treated with catheter-based intervention.
Out of the 83 conservatively managed patients, 33 required further intervention (CABG #19, PCI #14). Among the 12 patients with prior CABG, only 1 required re-do CABG. Among the 15 patients treated with coronary stent placement, 2 required a CABG procedure and 1 needed a second PCI. Overall, 21.2% of the patients who were treated conservatively following the diagnosis of SCAD underwent a surgical or catheter-based intervention, compared to 2.5% who received an early intervention after the diagnosis of SCAD (p = 0.001) (Figure 5).
Kaplan-Meier analysis showed that patients with an isolated single SCAD lesions in the left or right coronary artery had a statistically significant better outcome when treated with an early aggressive strategy, including CABG or stent placement as compared to conservative strategy (p = 0.023, p = 0.006, respectively). The analysis of combined left and right coronary arteries with single SCAD was also statistically significant in favor of aggressive strategy (p = 0.001) (Figure 6).
In our review, we found that 87 patients (19.8%) received thrombolytic therapy before SCAD was diagnosed. Of these 87 patients, the clinical condition of 52 (59.7 %) patients worsened, while 35 patients remained clinically stable. However, out of 35 stable patients after thrombolytic administration; 59% required further intervention later.
Intravascular ultrasound (IVUS) was used in 10.2% (n = 32) vs. 19.1% (n = 21) of patients during the first and second angiographic examinations, respectively.