Heart Beat: June 2018
Resting Blood Pressure May Predict Risk of Developing Hypertension
Blood pressure commonly rises with age. However, it has been impossible to predict who might develop hypertension, or when it might occur. A study published online March 21, 2018, in JAMA Cardiology shed light on this important issue. Using 1,252 participants in the long-term Framingham Study, researchers identified the presence of a threshold above which blood pressure tends to rise rapidly. Participants in this study underwent regular examinations approximately every two years starting at the mean age of 35.3. Their blood pressure was taken at each exam. Hypertension was defined as a blood pressure reading of 140/90 millimeters of mercury (mmHg) or higher or the use of antihypertension medications at two or more consecutive exams. The researchers noted the participants who developed hypertension and their age at the time of diagnosis. Systolic blood pressure readings leading up to the diagnosis were also recorded. In general, systolic blood pressure remained stable until it reached 120-125 mmHg, after which it accelerated rapidly toward hypertension. The authors noted that this finding supports new guidelines advocating the use of 130 mmHg as the threshold for defining hypertension, since lifestyle changes and/or medications may be needed earlier to prevent high blood pressure from developing.
Common Drugs May Help Protect the Heart from Chemotherapy Damage
It’s both a tragedy and an irony when a powerful chemotherapy agent cures a woman of breast cancer, only to leave her with heart failure or cardiomyopathy. It is not uncommon. Some of the most effective chemotherapy drugs used in the fight against breast cancer are known to be toxic to the heart. These include the anthracyclines, such as doxorubicin (Adriamycin™), and the monoclonal antibody trastuzumab (Herceptin™). The risk is great enough to cause some oncologists to discontinue using these effective drugs. A couple years ago, the angiotensin-receptor blocker candesartan (Atacand™) was found to offer some protection to patients who have just started taking anthracyclines. Now, a clinical trial presented at the American College of Cardiology Annual Scientific Sessions in March 2018 offered encouragement that the beta-blocker carvedilol (Coreg™) and the angiotensin-converting enzyme inhibitor lisinopril (Prinivil™) may protect certain patients taking these drugs, too. The trial enrolled 468 patients with HER-2 positive breast cancer and no evidence of heart failure, who were being started on a course of trastuzumab. Half were receiving anthracyclines simultaneously or had been previously treated with these drugs. All participants were randomized to receive carvedilol, lisinopril or placebo. After two years, neither drug had been shown to be more effective than placebo at protecting patients treated with trastuzumab alone. However, both carvedilol and lisinopril were slightly more effective than placebo at holding off the development of heart failure (measured as a 10 percent or greater drop in left ventricular ejection fraction) in patients who were also treated with anthracyclines.
New Anticoagulants Further Lower the Risk of a Second Heart Attack in Some
After a heart attack, the risk of a second heart attack is greatly increased. The antiplatelet drugs aspirin and clopidogrel (Plavix™) are given to patients to reduce this risk. In theory, oral anticoagulants should reduce the risk even further, but clinical trials using the standard anticoagulant, warfarin (Coumadin™), have produced conflicting results. Researchers wondered if the newer direct oral anticoagulants (DOACs)—apixaban, dabigatran, edoxaban and rivaroxaban—might be more effective. In a review of six clinical trials involving 29,667 patients, they determined that the addition of a DOAC to antiplatelet therapy reduced the combined risk of cardiovascular death, heart attack and stroke in patients who had suffered a full-blown heart attack (ST-elevation myocardial infarction, or STEMI), but only marginally reduced the risk in patients who had suffered a mild heart attack (non-ST-elevation myocardial infarction, or NSTEMI). As explained in the March 2018 issue of JAMA Cardiology, the benefit of adding a DOAC was offset by a significant increase in major bleeding events.