coronary angiography PCI

血之循環，命之所在， 保其健康，永續生機。

Precath checklist

• Peripheral arterial exam (radial, femoral, DP, PT pulses; bruits); palmar arch eval (eg, w/ pulse oximetry & plethysmography) not routinely done. ✓ can lie flat × hrs, NPO >6 h.
• ✓ CBC, PT-INR (ideally ≤2), Cr; hold ACEI/ARB if renal dysfxn. Blood bank sample.
• ↓ risk of contrast-induced kidney injury: hold ACEI/ARB/ARNI, NSAIDs, diuretics. PreRx w/ isotonic IVF: data mixed, but may be helpful if high risk (Lancet 2017;389:1312).
• If iodinated contrast allergy, preRx w/ steroids & antihistamines

Vascular access

• Radial access preferred for coronary angiography: ↓ major bleeding & vascular complications, and possibly mortality benefit (Circ CI 2018;11:e000035)
• Femoral artery commonly used; high puncture ↑ risk of retroperitoneal bleed; low puncture ↑ risk of arterial complic. (eg, AV fistula, superficial femoral artery cannulation)

Periprocedural pharmacotherapy for PCI

• ASA 325 mg × 1. P2Y12 inhibitor: ticagrelor or prasugrel preferred over clopidogrel in ACS. Outside of STEMI, preRx load not recommended when anatomy unknown. Cangrelor (IV P2Y12 inhib) ↓ peri-PCI events vs. clopi w/o PreRx (NEJM 2013;368:1303).
• GP IIb/IIIa inhibitor: sometimes added if periprocedural thrombotic complication
• Anticoagulant: UFH or bivalirudin (if HIT) typically given during case and stopped at end

PCI and peri-PCI interventions

• Physiology: fractional flow reserve (FFR): ratio of max flow (induced by adenosine) distal vs. prox to stenosis to ID hemodyn. signif. lesions (≤0.80). Instantaneous wave-free ratio (iFR) similar, doesn’t require vasodilator; iFR threshold ≤0.89 (NEJM 2017;376:1813 & 1824).
• Advanced imaging: intravascular U/S (IVUS) or optical coherence tomography (OCT)
• Drug-eluting stents (DES): ↓ cardiac death, MI, repeat revasc, & stent thrombosis vs. BMS (Lancet 2019;393:2503). Balloon angioplasty alone reserved for lesions too narrow to stent.

Peri-PCI complications

• No or slow reflow: Rx with local delivery of vasodilators
• Coronary artery dissection: treat with stent
• Coronary perforation: immediate balloon tamponade, ✓ for effusion, seal w/ covered stent

Vascular access post-PCI complications

• Postprocedure ✓ vascular access site, distal pulses, ECG, CBC, Cr
• Bleeding: reverse/stop anticoag (d/w interventionalist); IV fluids/PRBC/plts as required
  • hematoma/overt bleeding: manual compression
  • retroperitoneal bleed: may p/w ↓ Hct ± flank or back pain. CT abd/pelvis (I–) or angio if unstable. If does not auto-tamponade, intravascular balloon and/or covered stent.
• Vascular damage (~1% of dx angio, ~5% of PCI; Circ 2007;115:2666)

  • pseudoaneurysm: triad of pain, expansile mass, systolic bruit; diagnose w/ U/S;

    • Rx (if pain or >2 cm): U/S-directed thrombin injection, surgical repair if former fails

  • AV fistula: continuous bruit; Dx: U/S; Rx: surgical repair if large or sx

• limb ischemia (emboli, dissection, clot): cool, mottled extremity, ↓ distal pulses; Dx: loss of pulses, ↓ pulse volume recording, angio; Rx: percutaneous or surgical repair
• radial artery occlusion: if sx, consider 4 weeks LMWH

Other complications (NEJM 2017;377:1513)

• Contrast-induced AKI: w/in 48 h, peak 3–5 d; pre-hydration reasonable (see “CIAKI”)
• Stroke: ~0.1–0.4% of cases. Usually ischemic from atheroembolic event during cath. Rx depends on sx/location/timing but includes thrombectomy, tPA, DAPT if ischemic.
• Cholesterol emboli syndrome: typically in Pts w/ large burden Ao atheroma; mesenteric ischemia (abd pain, LGIB, pancreatitis); intact distal pulses but livedo and toe necrosis

Stent post-PCI complications

• Stent thrombosis: acute clot formation in stent usually in 1st mo but can occur anytime. Typically p/w AMI. Often due to premature d/c antiplt Rx or mech prob. (stent underexpansion or unrecognized dissection, typically presents early).
• In-stent restenosis: develops in previously stented segment mos after PCI. Typically p/w gradual ↑ angina. Due to elastic recoil and neointimal hyperplasia; ↓ w/ DES.

Duration of dual antiplatelet therapy (JACC 2016;68:1082 & EHJ 2018;39:213)

• DAPT duration determined by patient presentation (ACS vs. SIHD), long-term ischemic risk (patient and procedural risk factors), and bleeding risk
• Antiplt Rx: DAPT (ASA 81 + P2Y12 inhib) in SIHD for 4 wk (BMS) or ≥6 mo (DES); in ACS (qv) for 12 mo and possibly beyond (JAMA Cards 2016;1:627). Data emerging for DAPT 1–3 mo, followed by P2Y12 inhib monotherapy (Circ 2020;142:538).
• If need long-term oral anticoag, consider clopi+DOAC and consider stopping ASA (? after ~1 wk) as ↓ bleed, but trend small ↑ ischemic risk (JAMA Cardiol. 2020;5:582)