Cardio-Oncology for the Interventionalist—Part 2

By: Christine Gasperetti, MD, FSCAI, and Jayant Bagai, MD, FSCAI

Cancer patients who develop coronary events and require percutaneous coronary intervention (PCI) represent a challenging and unique subset of patients, due to their elevated risk of both bleeding and thrombosis. SCAI has published an Expert Consensus Statement for the management of cardio-oncology patients in the cardiac catheterization laboratory (CCL).¹ In Part 2 of the “Cardio-Oncology for the Interventionalist” Tip of the Month, we will summarize current recommendations from the SCAI consensus statement for management of cancer patients who present with acute coronary syndrome (ACS) and/or need PCI.

PCI in Setting of Cancer and Chemotherapy-Induced Thrombocytopenia

Platelet counts <100,000/ml are seen in 10% of cancer patients. Thrombocytopenia increases the risk of bleeding and also does not lower the elevated risk of thrombosis in cancer patients. This is because low platelet counts in cancer patients are not protective against ischemic events. Rather, they are associated with an increased propensity to develop thrombosis; a classic example is acute promyelocytic leukemia. Table 1 summarizes useful tips when taking care of a patient with significant thrombocytopenia who needs coronary angiography and/or PCI.

Precoronary angiography/PCI	There is no minimum platelet count that is an absolute contraindication to coronary angiography. A platelet count of 20-30,000/ml is sufficient to allow PCI if there are no additional coagulation abnormalities. Platelet counts above 50,000/ml are sufficient for surgical treatment when indicated. Thromboelastography may be considered to determine risk of intracranial bleeding in patients with a platelet count < 30,000/ml prior to PCI. For patients with reasonable expected survival, PCI should be performed for ST-segment elevation myocardial infarction (STEMI) and high-risk non-STEMI, or NSTEMI. PCI should be done with FFR guidance for severe stable angina that persists after medical therapy and control of precipitating factors. CABG can be considered when malignancy is curable or prognosis is good.
Access Site	Radial access is preferred, as it can lower bleeding complications in thrombocytopenic patients compared with femoral access. Heparin should be used at lower doses than usual. If femoral access is chosen, a meticulous technique using ultrasound and fluoroscopy should be used to access the common femoral artery. The smallest-sized sheath should be used. Meticulous flushing, early sheath removal, and ambulation are essential to prevent thrombotic complications.
During PCI	Use a lower dose of heparin (30-50 U/kg) as the initial dose in patients with a platelet count < 50,000/ml undergoing PCI and avoid GPI use. Standard dose heparin (50-70U/kg) or bivalirudin can be used for a platelet count > 50,000/ml. ACT of 250 seconds may still be achieved with lower bolus doses. Use FFR to assess hemodynamic significance of intermediate stenosis, especially bifurcation, ostial, and left main lesions. Consider PTCA alone for a platelet count < 30,000/ml or when a noncardiac surgery or procedure is needed urgently. Consider BMS for a platelet count > 30,000/ml and when there is a need for non-cardiac surgery or procedure which can be postponed for 4 weeks. Consider a newer-generation DES for a platelet count > 30,000/ml and when there is no immediate need for a surgery, a procedure, or chemotherapy. Use radial access and if femoral access is used, consider bivalirudin. IVUS/OCT should be used to ensure optimal stent expansion and apposition in case early DAPT interruption is needed.
Post-PCI	Aspirin should not be held in most thrombocytopenic patients with ACS due to worse outcomes, and it can be used when platelet counts are > 10,000/ml. For a platelet count < 50,000/ml, the following are recommended durations for DAPT: PTCA alone- 2 weeks, BMS- 4 weeks, and second- or third-generation DES- 6 months. DAPT can be used for platelet counts between 30-50,000/ml. Ticagrelor and prasugrel should not be used for a platelet count < 50,000/ml. Triple therapy should not be used. Prophylactic platelet transfusions should be considered for platelet counts < 10,000/ml, or < 20,000/ml for patients receiving treatment for solid/necrotic tumors at risk for bleeding.

Table 1 – Considerations for cancer patients undergoing PCI. FFR: fractional flow reserve; CABG: coronary artery bypass grafting; GPI: glycoprotein IIb/IIIa inhibitors; PTCA: percutaneous transluminal coronary angioplasty; BMS: bare-metal stent; DES: drug-eluting stent; IVUS: intravascular ultrasound; OCT: optical coherence tomography; DAPT: dual antiplatelet therapy. Adapted from reference 1.

Cancer and ACS

Cancer patients have almost twice the risk of developing ACS due to the presence of a proinflammatory and prothrombotic state. The highest risk for arterial thrombosis occurs in the first month after diagnosis and levels off in six months. The risk is also higher with more advanced stages of cancer and certain types of cancer such as lung, pancreas, and gastrointestinal (GI). Patients with both cancer and ACS are at a high risk for mortality. Primary PCI in patients with recently diagnosed cancer was associated with a threefold increase in mortality compared with controls, and cancer was the strongest independent predictor of in-hospital and one-year death in patients undergoing PCI for ACS.^2,3 In the largest series of cancer patients with ACS, only 3 percent of patients underwent PCI, with a one-year survival of only 26 percent.⁴Treatment must be individualized and determined with collaboration with oncology as studies have also shown that withholding treatment for patients with cancer can place these patients at higher risk of poor outcomes.

Specific considerations while treating cancers patients with ACS include:

There should be an awareness of a prothrombotic state and, therefore, a potentially higher risk of stent thrombosis.
Complex bifurcation stenting strategies or long segments of stent should be avoided. Use PTCA only, if feasible, and a newer-generation DES if stenting is required.
OCT or IVUS should strongly be considered to ensure optimal stent expansion and apposition. In a small, single-center study, patients with optimal stent imaging were able to safely interrupt DAPT to allow cancer treatment.⁵
At least one antiplatelet agent should be continued post-PCI when urgent surgery requires DAPT interruption, and reloading with clopidogrel should be performed after interruption.
Unique causes of ACS in cancer patients may include tumor embolism, severe coronary vasospasm or Takotsubo cardiomyopathy. The latter typically occurs after the first cycle of chemotherapy and has been most commonly reported after 5-FU and capecitabine

Conclusions

ACS is common in cancer patients and represents a management dilemma in the presence of thrombocytopenia and elevated bleeding risk. Interventionalists should familiarize themselves with recommendations for management of antiplatelet therapy and best practices for PCI in cancer patients to lower the risk of bleeding and thrombosis.

References

Iliescu CA, Grines CL, Herrmann J, et al. SCAI Expert consensus statement: Evaluation, management, and special considerations of cardio-oncology patients in the cardiac catheterization laboratory. Catheter Cardiovasc Interv. 2016 Apr;87(5):E202-23.
Velders MA, Boden H, Hofma SH, et al. Outcome after ST elevation myocardial infarction in patients with cancer treated with primary percutaneous coronary intervention. Am J Cardiol. 2013 Dec 15;112(12):1867-72.
Abbott JD, Ahmed HN, Vlachos HA, et al. Comparison of outcome in patients with ST-elevation versus non-ST-elevation acute myocardial infarction treated with percutaneous coronary intervention. Am J Cardiol. 2007 Jul 15;100(2):190-5.
Yusuf SW, Daraban N, Abbasi N, et al. Treatment and outcomes of acute coronary syndrome in the cancer population. Clin Cardiol. 2012;35(7):443-50.
Iliescu CA, Cilingiroglu M, Giza DE, et al. "Bringing on the light" in a complex clinical scenario: Optical coherence tomography-guided discontinuation of antiplatelet therapy in cancer patients with coronary artery disease (PROTECT-OCT registry). Am Heart J. 2017 Dec;194:83-91.

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