Interventional cardiologists face challenges with cancer in the cath lab
SAN DIEGO — As the field of cardio-oncology evolves, interventional cardiologists are now searching for answers to important questions about how best to treat the patient with cancer.
Currently, in patients, there are three major challenges, including the optimal approach to dual antiplatelet therapy discontinuation, addressing patients with thrombocytopenia and anemia, and the incorporation of research on novel mechanisms of ACS into clinical care, Konstantinos Marmagkiolis, MD, MBA, FACC, FSCAI, staff interventional cardiologist at Premier Heart and Vascular Group and Florida Hospital Pepin Heart Institute, said during a presentation at the Society for Cardiovascular Angiography and Interventions Scientific Sessions.
Complexity of DAPT discontinuation
“A major challenge we have right now is the need to prematurely stop dual antiplatelet therapy in patients with cancer remission or with newly diagnosed cancer who have received a stent,” Marmagkiolis said.
Newer third-generation stents have data to support discontinuation of DAPT at 3 or 6 months, and newer trials are evaluating discontinuation of the second antiplatelet agent as early as 1 month after stent placement, he noted.
However, patients with cancer are often treated for STEMI or high-risk ACS and would optimally be treated with 12 months of DAPT, as the surgery itself is a hypercoagulable state, according to Marmagkiolis.
These considerations raise two important questions.
The first question pertains to the appropriate bridging agent, he noted. One review published in the Journal of the American College of Cardiology in 2017 proposes two bridging strategies — one involving glycoprotein IIb/IIIa inhibitors and one involving cangrelor (Kengreal, Chiesi). The study, however, did not specifically focus on patients with cancer.
The second question relates to the use of OCT imaging before DAPT discontinuation. At present, the PROTECT-OCT registry published in the American Heart Journal in 2017 is the most sophisticated work in the field, according to Marmagkiolis. As a result of their findings, the PROTECT-OCT researchers recommend performing an in-depth analysis using OCT imaging of a previously placed stent before a patient with cancer undergoes surgery. Evaluation of the expansion coverage and stent apposition may help identify patients who may safely discontinue DAPT. Low-molecular-weight heparin was also used in this study, suggesting that it may be another treatment option for these patients, Marmagkiolis noted.
Nevertheless, both of these issues require study in future trials, he added.
Considerations in thrombocytopenia, severe anemia
Another major challenge for interventional cardiologists is how to invasively evaluate patients who have severe anemia and thrombocytopenia, which occur frequently in patients with cancer.
According to a study published in the Journal of the American College of Cardiology in 2015, diagnostic angiogram can be safely performed in patients with very low platelet counts and interventional cardiologists should not be afraid to perform a diagnostic procedure in these patients, Marmagkiolis said.
However, the question is what interventionalists should do if the patient requires PCI, he noted.
“[The SCAI expert consensus statement] recommends aspirin for patients with platelet counts less than 10,000 mL and clopidogrel for patients with platelet counts less than 30,000 mL. For patients with platelet counts greater than 30,000 mL, there shouldn’t be any issue with doing PCI the same way we’d do it otherwise. The question arises when the platelet count drops below 30,000 mL,” Marmagkiolis said.
However, there is still uncertainty regarding other aspects of treatment in these patients. For instance, it remains unclear whether clopidogrel or aspirin should be stopped in patients with newly placed stents whose platelet counts fall beneath the recommended levels for treatment or whether the patients should be transfused with platelets to maintain the appropriate platelet count for continuing therapy.
“Again, this is a question we don’t have the answer to, but hopefully over the next year, we’ll have more information on what the best approach is for these patients,” Marmagkiolis said.
New ACS mechanisms
During the past several years, research on novel mechanisms of ACS in patients with cancer has emerged. Specifically, in the last year, researchers have found that embolization of cancer cells in the coronary arteries, as opposed to just thrombosis, may be responsible for STEMI in these patients, Marmagkiolis noted.
“This might partially explain why those patients have a high risk for STEMI. It might also explain why they do not do as well as we expect after PCI. Theoretically, if we leave the cancer cells in the coronaries, those cells are going to attract more platelets and will close earlier,” Marmagkiolis said. “That raises the question of how many STEMIs in patients with cancer are truly STEMIs in the way that we think of them and how many are really malignant embolizations?”
The only way to know for sure, he said, is to aspirate and send the debris for a pathology report. Although the guidelines no longer recommend aspiration thrombectomy, it may be worth considering for patients with cancer, he noted.
Another issue is that patients with cancer are also at a higher risk for takotsubo cardiomyopathy, according to Marmagkiolis.
“This is important because most cardiologists will not take the patient to the cath lab and will empirically give aspirin or clopidogrel,” Marmagkiolis said. However, these agents can unnecessarily increase the risk for bleeding in these patients.
Takotsubo cardiomyopathy is increased because of coronary hyperreactivity, endothelial dysfunction and spasm, according to Marmagkiolis. “So, this raises the question of why coronary angiograms are not performed, especially in patients with anemia and thrombocytopenia,” he said.
“ACS in the patient with cancer is a very complex situation, but we think over the next few years, we will figure out what is the best approach in the cath lab,” he said. – by Melissa Foster
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Disclosure: Marmagkiolis reports no relevant financial disclosures.