Your muscles stretch, but did you know your blood vessels can, too? Find out how high blood pressure (hypertension) can stress your heart without you even knowing it. If left untreated, high blood pressure can cause a stroke or heart attack. If you struggle with high blood pressure, we can help. The Complex Hypertension Clinic at BIDMC provides care for patients who, despite treatment with multiple medications, have been unable to keep blood pressure under control.