Chapter 21 Marini Acute Coronary Syndromes

452

SECTION II • Medical and Surgical Crises

Chest Pain

Targeted H&P 12 Lead ECG O 2 , Morphine, S/L NTG

STEMI on ECG

Lytic Eligible

Not Lytic Eligible

Start Heparin, b -Blocker

Door to Puncture <90 min Door to Puncture >90 min

Emergent Cath / PCI*

Emergent Cath / PCI

Lytic Rx

Transfer to Cath Facility or Activate Cath Lab

For Nearly All Post MI Pts: ASA, ACEI, b -Blocker Echo to Risk-Stratify

Ischemia, Instability,  ST?

Yes

No

Emergent Cath / PCI

Cath before D/C

FIGURE 21-6. ST elevation MI (STEMI) management algorithm. ACEI, angiotensin-converting enzyme inhibitor; NTG, nitroglycerin; PCI, percutaneous coronary intervention.

factors V and VIII, and increasing levels of fibrin degradation products. Unfortunately, none of these drugs can distinguish a “good” from a “bad” clot; therefore, all are associated with some increased risk of hemorrhage. The risk of bleeding is prob- ably highest with r-PA and lowest with SK. Of all the available agents, the fibrin-specific agents are most effective in achieving a patent infarct-related vessel (80% with fibrin-specific agents compared to 50% to 60% with SK). Unfortunately, the accel- erated t-PA regimen followed by an intravenous heparin infusion is associated with higher risk of major bleeding (including IC hemorrhage) than is SK. The rates of achieving a patent vessel are simi- lar among t-PA, r-PA, and TNK-tPA. The bleed- ing risk is lower with TNK-tPA, as compared to the other fibrin-specific agents. TNK-tPA and r-PA are administered as bolus doses and are, therefore, much easier to administer compared to acceler- ated t-PA regimen. Therefore, the agent of choice (in the United States) is TNK-tPA, but SK con- tinues to be popular in Europe and Asia, mainly

because of lower costs. SK may also be preferable in older patients (>75 years of age), particularly for small-sized women, if PCI is not available. P atient S election and I mportant F acts R egarding F ibrinolytic T herapy • See Tables 21-3 and 21-4 for indications and contraindications of fibrinolytic therapy. Table 21-3.  Indications for Thrombolytic Therapy ANGINOID CHEST PAIN OF LESS THAN 12-HOURS DURATION PLUS one or more of these: • ST elevation ≥ 1 mm in at least two contiguous LIMB leads • ST elevation ≥ 2 mm in at least two contiguous CHEST leads • New LBBB LBBB, left bundle-branch block.