After receiving change-of-shift report about the following four clients. Which client should the nurse assess first?

A. 59-year-old with unstable angina who has just returned to the unit after having a heart catheterization with balloon angioplasty.: This client is at highest risk for immediate, life-threatening complications following an invasive cardiac procedure. Post–cardiac catheterization risks include retroperitoneal hemorrhage, arterial occlusion, and re-occlusion of the coronary artery, requiring close hemodynamic and cardiac monitoring, making this the priority. B. 56-year-old client with chronic stable angina who is due to receive a dose of nifedipine.: Chronic stable angina is a predictable condition managed with medications such as calcium channel blockers. While timely medication administration is important, this client is stable and does not pose an immediate threat compared to a post-procedure client. C. Client who is post coronary artery bypass with potassium 4.2 mEq/L.: A potassium level of 4.2 mEq/L is within the normal range (3.5–5.0 mEq/L), indicating stable electrolyte status. Although post-CABG clients require monitoring, there is no evidence of acute instability or complication that would necessitate immediate assessment. D. 65-year-old who had a myocardial infarction (MI) 4 days ago and is anxious about the planned discharge.: Anxiety after an MI is common and should be addressed through therapeutic communication and education. However, this is a psychosocial concern rather than an immediate physiological threat, making it a lower priority.