乌鸦传媒

A 34-year-old woman presented to the hospital after calling the emergency medical service (EMS) due to prolonged constrictive pain in her chest, which had come on suddenly at home. Records showed that she was a smoker.

The EMS team performed a twelve-lead ECG, which revealed anterior ST-segment elevation with reciprocal ST depression in the inferior leads. Because it was going to take more than 2 hours to get the patient to the catheterization laboratory, they immediately started her on an IV loading dose of 250-mg aspirin and oral P2Y12 inhibitor (clopidogrel 300 mg), low-molecular-weight heparin, and an IV bolus of 7,000 IU of tenecteplase (TNKase).

About 15 minutes later, the patient went into cardiac arrest due to ventricular fibrillation. EMS responders immediately started cardiopulmonary resuscitation, including electrical defibrillation, which restored a palpable pulse. She was administered 300 mg IV amiodarone (Cordarone), intubated and regained a pulse (low-flow 5 min, now-flow 0). She was transported to a treatment center for coronary angiography. However, noting that the patient was showing signs of hemodynamic deterioration, clinicians started her on a dobutamine infusion.

The clinic team performed coronary angiography using a radial artery approach and identified an acute blockage with staining contrast of the ostium of the proximal segment of the left anterior descending (LAD) coronary artery. The occlusion did not respond to treatment with intracoronary nitrates. The Thrombolysis in Myocardial Infarction (TIMI) flow was grade 0, although the other coronary arteries were normal.

Using the right femoral artery, clinicians implanted an intra-aortic balloon pump (IABP), and were able to place a workhorse wire in the distal lumen of the LAD, thus restoring blood flow into the LAD to TIMI 2. Then the team implanted a long drug-eluting stent from the left main stem toward the proximal LAD covering the LAD lesion, restoring TIMI flow to grade III.

Clinicians noted that the need to perform the procedure simply and quickly meant that they did not protect the left circumflex artery. As a result, its ostium was pinched without flow deterioration following implantation of the stent. However, given the need to manage spontaneous coronary artery dissection in this young patient with evidence of occlusion and the fragility of the coronary arteries, clinicians decided not to continue with further optimization techniques. They decided to assess the patient after she was stabilized and perform an eventual proximal optimizing technique if required.

Echocardiographic assessment following angioplasty showed that the patient's left ventricular ejection fraction (LVEF) was significantly reduced (20%), and she had severe anterior hypokinesia in the absence of mechanical complications or pericardial effusion.

After receiving reperfusion, an IABP, and a dobutamine infusion, the patient remained hemodynamically unstable, leading clinicians to administer low-dose norepinephrine.

They performed a detailed physical examination which showed very marked paleness associated with pain in the abdomen and a low hemoglobin level. They performed an abdominal CT scan which revealed a massive hemoperitoneum and active bleeding from the liver. As a result, clinicians discontinued the dual antiplatelet therapy. The patient was given a blood transfusion and adrenaline infusion which resulted in a short-term stabilization, which was maintained by distal hepatic artery embolization followed by packing. They started the patient on aspirin the following day, and 6 days later, after managing the bleeding and stabilizing the patient, the team replaced clopidogrel with ticagrelor (Brilinta).

Nine days after undergoing surgery, the patient was discharged home with a medication regimen of aspirin, ticagrelor, ACE inhibitor, beta-blocker, and statin, as recommended in the guidelines.

Three months later, she returned for follow-up, reporting no further symptoms or events. At that time, a routine follow-up angiography showed a normal appearance of the coronary arteries, with TIMI grade III flow.

The first optical coherence tomography (OTC) showed that a minor left main stem stent had not fully expanded, which clinicians addressed using a proximal optimizing technique with a well-sized non-compliant balloon. The second OCT revealed a well-apposed and expanded stent from the left main stem to the proximal LAD and residual hematoma as a lunar crescent, supporting their earlier suspicion that the patient's symptoms had been due to LAD spontaneous coronary artery hematoma.

A subsequent follow-up echocardiogram indicated that the patient's LVEF had improved to 45%, although anterior wall motion abnormalities persisted.

Discussion

Clinicians reporting this of cardiac arrest after initial thrombolytic therapy in a young woman with STEMI related to coronary artery dissection noted that their patient's case reinforces previous reports linking thrombolysis with poor outcomes in patients with SCAD.

The authors explained that she was given thrombolytic therapy because it was expected to take more than 120 minutes for her to arrive at the clinic for treatment, "which represents 'golden hours' for considering primary PCI according to American and European ."

The group suggested that SCAD – which is increasingly recognized and noted to be and older individuals than previously thought – might be due to a prolonged coronary artery spasm in many cases. However, that does not explain this case, they wrote, given that the LAD occlusion persisted despite treatment with intracoronary nitrate during angiography. Given that their patient was a smoker, they suggested that STEMI may have been triggered by a plaque rupture. "Our case was complicated by sudden cardiac arrest related to ventricular fibrillation, which may reflect a potential intramural hematoma extension favored by thrombolysis," they added.

The group referenced several reports of negative outcomes in patients treated with fibrinolytics. However, they also suggested that their patient's hemorrhagic complication may have been related to liver damage and rib fracture that occurred during CPR for cardiac arrest in the context of potent antithrombotic medications, including antiplatelet therapy. "This should prompt discussion about contraindication of thrombolytics when SCAD is the most plausible STEMI underlying mechanism owing to the risk of dissection expansion or coronary intramural hematoma formation," case authors suggested.

In fact, SCAD affects about 20% of women younger than age 50 with , which demonstrates the relevance of fibrinolysis, they noted. Based on the strong suspicion that their patient had SCAD, they performed emergency PCI without using OCT imaging, due to the patient's hemodynamic instability. Nevertheless, they noted that "in the case of dissection with an obvious radiolucent flap, OCT can be of great help by guiding guidewire placement in the true lumen and choosing the optimal stent size and landing zone in order to cover all the eventual intramural hematoma."

Use of a cutting balloon would have benefitted in this case as well, had it been available, they wrote; adding that there is support for use of a cutting balloon in the distal part of the occlusion. It might have lowered the "risk of hematoma extension distally or proximally," as occurred in this patient, although "fortunately, as a tiny shift in ostial LCX." It might have also changed the ostial LAD stenosis caused by hematoma and possibly obviated the need to stent the left main stem.

Case authors emphasized that "PCI, in the context of SCAD, is very challenging due to the increased risk of extending the dissection or hematoma progression." They added that PCI has a relatively lower than in atherosclerotic acute coronary syndrome.

Indeed, authors of a retrospective study of 189 patients with a first SCAD episode reported that "by conventional criteria for PCI success/failure (residual stenosis), occurred in 53% overall. Using SCAD-specific criteria (flow-based), failure rate was 30%." However, they added that the extent of vascular patency at presentation had no effect on rates of PCI failure or on the need for emergency coronary artery bypass grafting.

Compared with conservative management, has been associated with an increased risk of poor outcomes such as in-hospital mortality and major cardiac adverse events, case authors added, concluding that "medical management should be the standard of care" and use of PCI limited to high-risk patients, such as those "with hemodynamic instability, persistent chest pain, or large myocardial involvement."

Case authors noted that the cause of their patient's SCAD was confirmed 3 months after her surgery, by OCT imaging which revealed remnants of the intramural hematoma. "PCI was covered by use of an intra-aortic balloon pump to optimize hemodynamic status, even though current data do not support its routine use," they wrote. "That decision was legitimately questionable."

Considerations around secondary prevention of sudden cardiac death in this case represent an "important discussion point," they said, noting the absence of published randomized clinical trials comparing conservative medical treatment with use of an implantable cardioverter defibrillator (ICD) for patients with SCAD and sudden cardiac death. While current research suggests that the role of ICD therapy may be limited to "secondary prevention in the absence of reversible causes," case authors referenced a recent retrospective that showed no secondary prevention benefit of ICD in the 11 of 208 SCAD patients studied who suffered sudden cardiac arrest.

They noted that their case study patient's left ventricular function was compromised in the short-term "and justified an optimal guideline-directed medical therapy to improve LVEF before considering ICD implantation," or alternatively, a wearable defibrillator for the acute and subacute phases.

The group concluded that although cardiac arrest may trigger diagnosis of SCAD, patient outcomes will be compromised without timely treatment response. In this case, cardiac arrest was likely due to thrombolysis-induced extension of hematoma, they suggested, concluding that while conservative treatment is central to SCAD management, "PCI must be considered if there is evidence of ongoing ischemia or large amount of jeopardized myocardium."

Comment