Should We Drain Pericardial Effusions in Aortic Dissection?
Introduction
Ascending aortic dissection, also known as type-A aortic dissection, carries a very high morbidity and mortality rate. One of the leading causes of mortality is cardiac tamponade associated with dissection into the pericardium. It has long been taught that draining pericardial fluid in type-A dissections is contraindicated. This contraindication was based on the thought that complete drainage results in increased atrial pressure and worsening of the tear/leak leading to catastrophic results from drainage. However, the current recommended approach takes into consideration that partial and repeated small volume drainage may provide the benefits of having a small volume of fluid in the pericardium as well as prevent death from tamponade physiology. This article presents a case of aortic dissection with pericardial tamponade.
The Case
60-year-old man with a history of PAD, left SFA stent, coronary artery disease, asthma, and CKD presents with one day of left leg pain. He used cocaine earlier today. The triage nurse found the patient to be in severe pain and thrashing around in his waiting-room chair. He was moved to a hallway bed and on initial examination he was found to have no pulse in his left leg, so he was moved to a resuscitation bay. He then became hypotensive and a point of care ultrasound revealed a pericardial effusion. His blood pressure improved with crystalloid fluids and a CTA showed a type-A aortic dissection with extension to the left iliac. Esmolol was started for rate (i.e. impulse) control but the patient frequently became hypotensive requiring fluids and cessation of esmolol. Impulse control therapy with beta-blockers and calcium channel blockers was abandoned due to the lability of the patient’s blood pressure.
Clinical Course
The patient was flown to a large medical center for intervention by the cardiothoracic surgery team. He immediately underwent aortic root repair, among a multitude of other complex intraoperative techniques, but his operative course was complicated by multiple episodes of cardiac arrest and hypotension. In the postoperative period he was noted to have mottled lower extremities and concern for spinal cord ischemia. His family eventually made him DNR with comfort care and he died shortly thereafter.
Discussion
The decision to drain pericardial fluid in the emergency department is based largely on the hemodynamic stability of the patient. It is generally recommended by cardiothoracic surgeons that patients with type-A aortic dissection be managed with impulse control by lowering the heart rate to 50-60 bpm using a beta-blocker such as esmolol and their systolic blood pressure to at least less than 120mmHg using agents like calcium channel blockers in conjunction with beta-blockers if needed. Patients who have a type-A dissection with pericardial fluid may be in tamponade physiology with tachycardia and hypotension, precluding the clinicians ability to utilize beta-blocker or calcium channel blocker therapy.
The 2015 European Society of Cardiology (ESC) guidelines for the diagnosis and management of pericardial diseases recommend in the setting of aortic dissection with hemopericardium, small volume incremental drainage be performed to maintain a blood pressure of around 90mmHg (class IIa, level C). There is a study by Hayashi et al. that provides the basis for this therapeutic approach. In this study, patients with aortic dissection and hypotension from cardiac tamponade received two 500mL of crystalloid boluses. If this did not result in hemodynamic improvement, they then moved to placing a pericardial drain and draining approximately 5-10mL of pericardial fluid at a time to improve hemodynamics. Any time the patient’s blood pressure dropped below 80mmHg, 5-10mL of fluid was drained until improvement and ultimately operative repair. This resulted in a mortality reduction from 40% typical of tamponade in dissection to about %17 in the study population.
The authors used ultrasound to find the thickest area of fluid in the 4-5th intercostal space in the midclavicular line (rather than subxiphoid because the 4-5th space is thought to have more fluid in these cases) followed by modified seldinger technique to place a drain (a central venous catheter with a stopcock can be used in facilities without pericardial drainage kits).
Conclusion
In acute type-A aortic dissection, mild tamponade physiology may provide benefit due to lowered blood pressures and a form of natural impulse control. However, moderate-to-severe tamponade has a significant amount of mortality associated with it. In these cases, placement of a pericardial drain and performance of incremental drainage of 5-10mL of pericardial fluid to maintain blood pressure around 90mmHg systolic may provide significant mortality benefit and is in alignment with the ESC guidelines.
References
- Impact of controlled pericardial drainage on critical cardiac tamponade with acute type A aortic dissection: https://pubmed.ncbi.nlm.nih.gov/22966000/
- 2015 ESC Guidelines for the diagnosis and management of pericardial diseases: The Task Force for the Diagnosis and Management of Pericardial Diseases of the European Society of Cardiology (ESC)Endorsed by: The European Association for Cardio-Thoracic Surgery (EACTS): https://pubmed.ncbi.nlm.nih.gov/26320112/