What is the primary risk associated with late presentation STEMI?

The primary risk associated with late presentation of ST-Elevation Myocardial Infarction (STEMI) is indeed a higher risk for complications. When a patient experiences a STEMI and arrives late for treatment, the duration of ischemia increases, leading to more substantial damage to the myocardial tissue.

As time progresses without reperfusion therapy, such as percutaneous coronary intervention (PCI), the likelihood of experiencing severe complications rises. These complications can range from heart failure to arrhythmias, or even cardiac arrest due to the extensive damage caused to the heart muscle. In addition, late presentation can lead to an increased risk of mortality.

While other options may relate to aspects of STEMI management, they don't encapsulate the overarching risk posed by delays in treatment as comprehensively as the higher risk for complications does. The longer the heart is deprived of blood flow, the less favorable the outcome becomes, thus elevating the potential for adverse events significantly.