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Arrhythmias, Acute Coronary Syndromes, and Hypertensive Emergencies

Ryan Malcom, MD

Division of Trauma and Acute Care Surgery, New York Medical College, Westchester Medical Center, Valhalla, NY, USA

A 62‐year‐old woman with a smoking history was hospitalized with a bleeding duodenal ulcer. She has been managed nonoperatively thus far. On hospital day 2, she complains of chest pain and dyspnea. She is administered oxygen, nitroglycerin, and morphine. CBC, coagulation studies, and cardiac marker levels are drawn. The following is seen on a 12 lead EKG:

Figure 4.1 EKG.

The next best step in the treatment of this patient is:
1. Immediate transfer to the catheterization laboratory
2. Administration of aspirin
3. Obtain chest x‐ray
4. Fibrinolysis
5. Administration of ibuprofen
The 12 lead EKG is central to the identification of ST‐segment elevation myocardial infarction (STEMI). Elevated ST‐segment elevation in two contiguous leads, or a new left bundle branch block (LBBB), characterizes STEMI. This patient has a STEMI. Usually, patients with STEMI have a complete occlusion of an epicardial coronary artery. To save heart muscle and reduce complications of myocardial infarction (MI), urgent treatment is required. The treatment of STEMI is early reperfusion therapy via either fibrinolysis or percutaneous coronary intervention (PCI). PCI is preferred if a catheterization laboratory is immediately available, otherwise fibrinolysis should be initiated. Transport to the catheterization laboratory should not be delayed for a CXR or cardiac marker lab results. This patient has a GI bleed, and therefore, fibrinolysis and aspirin are contraindicated. Nonsteroidal anti‐inflammatory drugs (i.e. ibuprofen), excluding aspirin, are contraindicated because of increased risk of mortality with STEMI.

Answer: A

Antman EM, Anbe DT, Armstrong PW, et al. ACC/AHA guidelines for the management of patients with ST‐elevation myocardial infarction. J Am Coll Cardiol. 2013; 61:485–510.

Antman EM, Anbe DT, Armstrong PW, et al. ACC/AHA guidelines for the management of patients with ST‐elevation myocardial infarction. Circulation. 2018

Pinto DS, Kirtane AJ, Nallamothu BK, et al. Hospital delays in reperfusion for ST‐elevation myocardial infarction: implications when selecting a reperfusion strategy. Circulation. 2006; 114(19):2019–2025.

Kimmel SE, Berlin JA, Reilly M, et al. The effects of nonselective non‐aspirin non‐steroidal anti‐inflammatory medications on the risk of nonfatal myocardial infarction and their interaction with aspirin. J Am Coll Cardiol. 2004; 43(6):985–990.
A 57‐year‐old man with a history of coronary artery disease (CAD) has a bowel resection and ventral hernia repair for strangulated hernia. On postoperative day 3, he has new‐onset chest pain. Which of the following most increases his risk for a major adverse cardiovascular event (MACE: death, nonfatal myocardial infarction, or urgent need for coronary revascularization)?
1. New‐onset chest pain lasting 10 minutes
2. ST depression of 0.3 mm on his EKG
3. Troponin I two times normal value
4. Age greater than 50
5. Male gender
When chest pain is likely caused by CAD, there are assessments available for risk stratification. The Braunwald and thrombolysis in myocardial infarction (TIMI) risks scores are used for risk stratification. TIMI has become the primary tool for therapeutic recommendations. Neither recent surgery nor gender are included. Age does not become a predictor variable until age > 65 in the TIMI risk score. An ST depression is diagnostic when > 0.5 mm; less than 0.5 mm is nonspecific. In both scoring systems, elevated cardiac markers including troponin is a predictive variable and portend a high risk.

Answer: C

Antman EM, Cohen M, Bernink PJ, et al. The TIMI risk score for unstable angina/non‐ST elevation MI: a method for prognostication and therapeutic decision making. JAMA. 2000; 284(7):835–842.

Braunwald E, Antman EM, Beasley JW, et al. ACC/AHA guideline update for the management of patients with unstable angina and non–ST‐segment elevation myocardial infarction‐‐2002: summary article: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on the Management of Patients With Unstable Angina). Circulation. 2002; 106(14):1893–1900.
The most important factor in improving survival during STEMI is:
1. Early intubation
2. Timely reperfusion
3. Giving aspirin
4. Smoking cessation
5. IV metoprolol
ST elevation begins after occlusion of a coronary artery. Myocardial cell death proceeds rapidly until re‐establishment of blood flow. Reperfusion with fibrinolytic therapy and/or PCI can limit loss of heart muscle. The majority of infarct occurs by four hours after the onset of symptoms, and after 6 hours the infarct in nearly complete. Sudden cardiac death is most likely to develop during the first 4 hours after onset of symptoms. Reperfusion has been shown to reduce mortality, preserve LV function, and limit the development of congestive heart failure. Intubation is not indicated in STEMI unless there is associated respiratory distress. Smoking cessation is a long‐term preventive strategy and is not applicable acutely. Aspirin is indicated in the initial management and is complementary to fibrinolysis and reperfusion. Metoprolol may be helpful but is not the most important factor in improving survival.

Figure 4.2 TIMI risk assessment.

Figure 4.3 Braunwald risk assessment.

Answer: B

O’Connor RE, Al Ali AS, Brady WJ, et al. Part 9: acute coronary syndromes: 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2015; 132(18) (suppl 2):S483–S500.

Campbell RW, Murray A, Julian DG . Ventricular arrhythmias in first 12 hours of acute myocardial infarction: natural history study. Br Heart J. 1981; 46(4):351.

A 49‐year‐old mother of seven has a history of diabetes ellitus, hypertension, smoking, and 4 months ago underwent PCI with a paclitaxel‐eluding stent placement for unstable angina. Her medications include aspirin, clopidogrel, metoprolol, HMG‐CoA reductase inhibitor, metformin, and an angiotensin‐converting enzyme (ACE) inhibitor. She now presents to your office with one episode of right upper quadrant pain and based on history, physical exam, labs, and ultrasound, you diagnose her with biliary colic and cholelithiasis. Of the following choices, which is the next best step in management?

Delay the operation for 6 months.
Stop aspirin and clopidogrel, and proceed with the operation in 5 days.
Stop aspirin and clopidogrel, and proceed with the operation in 7 days with a preoperative heparin infusion as a bridge to surgery.
Stop clopidogrel, continue aspirin, and proceed with surgery.
Transfuse platelets, and proceed with surgery.

In patients with coronary stents, dual antiplatelet therapy is recommended for at least one year to minimize the risk of stent thrombosis. Large observational studies suggest an increased risk of stent thrombosis for at least 6 months. A cholecystectomy is elective at this time. To stop, or adjust, dual antiplatelet therapy less than 6 months after placement of the stent risks thrombosis, and to operate on dual antiplatelet therapy increased bleeding complications. In the recommendations below, there are differences between bare‐metal stents (BMS) and drug‐eluding stents (DES). A biological explanation for these differences is the earlier endothelialization of bare‐metal stents.

COR	LOE	Recommendations
I	B‐NR	Elective noncardiac surgery should be delayed 30 days after BMS implantation and optimally 6 months after DES implantation.
I	C‐EO	In patients treated with DAPT after coronary stent implantation who must undergo surgical procedures that mandate the discontinuation of P2Y₁₂ inhibitor therapy, it is recommended that aspirin be continued if possible and the P2Y₁₂ platelet receptor inhibitor be restarted as soon as possible after surgery.
IIa	C‐EO	When noncardiac surgery is required in patients currently taking a P2Y₁₂ inhibitor, a consensus decision among treating clinicians as to the relative risks of surgery and discontinuation or continuation of antiplatelet therapy can be useful.
IIb	C‐EO	Elective noncardiac surgery after DES implantation in patients for whom P2Y₁₂ inhibitor therapy will need to be discontinued may be considered after 3 months if the risk of further delay of surgery is greater than the expected risks of stent thrombosis.
III: Harm	B‐NR	Elective noncardiac surgery should not be performed within 30 days after BMS implantation or within 3 months after DES implantation in patients in whom DAPT will need to be discontinued perioperatively.

Answer: A

Levine GN, Bates ER, Bittl JA, et al. 2016 ACC/AHA guideline focused update on duration of dual antiplatelet therapy in patients with coronary artery disease. Circulation. 2016; 134(10):e123–e155.

This same patient turns 50‐years‐old 8 months after cardiac stent placement and needs a colonoscopy as recommended by her primary care physician. A sigmoid colon cancer is discovered. The most appropriate plan for her operation and antiplatelet medication is to:
1. Delay the operation for 4 months to perform at the same time as cholecystectomy.
2. Stop aspirin and clopidogrel, and operate after 7 days.
3. Stop aspirin and clopidogrel, operate after 7 days, and bridge with enoxaparin.
4. Stop clopidogrel, continue aspirin, and operate after 5 days.
5. Continue both clopidogrel and aspirin, and proceed with intraoperative platelet transfusion.
At this time the surgery is for a malignancy and cannot wait months. The recommendation for urgent noncardiac surgery for a patient on dual antiplatelet therapy is to stop the clopidogrel and continue aspirin. This recommendation is based on expert opinion. For patients undergoing laparoscopic surgery, continuation of a single antiplatelet agent is not associated with an increased risk of preoperative bleeding. Since there is not an increased risk of bleeding, there is no indication for platelet transfusion. There is no role for enoxaparin bridge because it is not an antiplatelet agent. These are complex decisions and should be reached by consensus of the surgeon, cardiologist, anesthesiologist, and patient. When intraoperative platelet transfusion is given, it may cause thrombosing the stent.

Answer: D

Levine GN, Bates ER, Bittl JA, et al. 2016 ACC/AHA guideline focused update on duration of dual antiplatelet therapy in patients with coronary artery disease. Circulation. 2016; 134(10):e123–e155.

Antolovic D, Rakow A, Contin P, et al. A randomised controlled pilot trial to evaluate and optimize the use of anti‐platelet agents in the perioperative management in patients undergoing general and abdominal surgery—the APAP trial (ISRCTN45810007). Langenbecks Arch Surg. 2012; 397(2):297–306.

Fujikawa T, Tanaka A, Abe T, et al. Does antiplatelet therapy affect outcomes of patients receiving abdominal laparoscopic surgery? Lessons from more than 1,000 laparoscopic operations in a single tertiary referral hospital. J Am Coll Surg. 2013; 217(6):1044–1053.

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