Should Isosorbide Be Stopped Before Cardiac Catheterization?
No, isosorbide (isosorbide mononitrate or dinitrate) does not need to be stopped before cardiac catheterization and can be safely continued through the procedure.
Rationale for Continuation
The available guidelines focus extensively on antiplatelet and anticoagulant management before cardiac catheterization but do not recommend discontinuing nitrates like isosorbide 1, 2, 3. This absence of any recommendation to stop nitrates is clinically significant—if discontinuation were necessary, it would be explicitly stated given the comprehensive nature of these periprocedural guidelines.
Nitrates are fundamentally different from antiplatelet agents and anticoagulants in their mechanism and bleeding risk profile. Unlike clopidogrel, aspirin, or anticoagulants that require specific timing considerations before invasive procedures 1, 4, nitrates work through vasodilation and do not affect hemostasis or increase procedural bleeding risk 5, 6.
Supporting Evidence for Safety
Research demonstrates that isosorbide dinitrate can be safely administered perioperatively, including immediately before and after procedures, with minimal complications 7. In a study of 152 cardiac patients undergoing noncardiac surgery, sublingual isosorbide dinitrate given preoperatively resulted in only 1.9% cardiovascular complications with 0% mortality 7.
Isosorbide produces beneficial hemodynamic effects including coronary artery dilation (up to 51% in diseased segments), reduced preload and afterload, and decreased myocardial oxygen demand—all potentially advantageous during cardiac catheterization 5, 6.
The drug's mechanism of reducing venous return, arterial blood pressure, and ventricular mechanical work makes it protective rather than problematic during invasive cardiac procedures 6.
Contrast with Medications That Must Be Stopped
The guidelines are explicit about which medications require discontinuation before cardiac catheterization:
- Anticoagulants (DOACs, warfarin) must be held for 24-120 hours depending on the specific agent, renal function, and vascular access site 1
- Clopidogrel should be withheld until coronary anatomy is defined if CABG cannot be excluded, though it can be continued in unstable patients 1, 2, 3
- Aspirin, notably, should be continued through catheterization 2, 3
The fact that nitrates are never mentioned in these detailed periprocedural medication management algorithms confirms they do not require discontinuation.
Clinical Management Approach
- Continue isosorbide at the patient's usual dose through the catheterization procedure 7, 5, 6
- Ensure adequate hydration, as nitrates cause vasodilation and patients may be more sensitive to volume depletion during the procedure 5, 6
- Be aware that additional intravenous nitroglycerin is commonly administered during cardiac catheterization itself for coronary vasodilation, demonstrating the safety and utility of nitrates during these procedures 5
- Monitor blood pressure, as the combination of chronic oral nitrates plus procedural sedation and contrast may occasionally cause hypotension, though this is manageable and not a contraindication to continuation 7, 6