Endocarditis and Valve Emergencies

In depth

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How endocarditis forms, who gets it and how it presents

Turbulent jets, catheters, device leads and injected particles injure valve endothelium, and platelets and fibrin settle there as a sterile thrombus. Bacteremia from teeth, skin, gut or a line seeds it, and good adherers, above all S. aureus, which can also invade intact endothelium, build a vegetation of fibrin, platelets and bacteria in a biofilm. There, dense, slow-growing bacteria are shielded from neutrophils and tolerate antibiotics, so cure takes weeks of bactericidal therapy or surgery (ESC 2023).

Harm spreads three ways: local destruction (perforation, chordal rupture, abscess, fistula, heart block), emboli (brain, spleen, kidneys, limbs, coronaries; lungs in right-sided IE) and immune complexes (glomerulonephritis, Osler nodes, Roth spots). Incidence was 13.8 per 100,000 in 2019 and rises with age, prosthetic valves, devices, dialysis and injection drug use. In-hospital mortality has stayed at 15–30% for two decades and exceeds 45% in S. aureus prosthetic valve IE (ESC 2023).

Diagnosis: two 2023 criteria sets, cultures and imaging

Both 2023 systems keep the Duke arithmetic (definite: 2 major, 1 major + 3 minor, or 5 minor; possible: 1 major + 1 minor, or 3 minor) but count more evidence and differ in details.

Bacteremia in IE is continuous, so cultures need not wait for a fever spike, and one positive bottle is weak evidence. ESC 2023 asks for at least 3 sets 30 minutes apart, 10 mL per bottle, from peripheral veins rather than catheters, before antibiotics. Culture-negative IE is usually due to prior antibiotics; then send Coxiella and Bartonella serology and PCR or 16S sequencing of valve tissue.

TTE is first line (ESC 2023, Class I) but misses small vegetations, prosthetic lesions and abscesses, so TEE follows in nearly everyone except clear isolated right-sided native valve IE; repeat both in 5–7 days if suspicion persists. Cardiac CT beats TEE for abscess and pseudoaneurysm; echo is better for small vegetations and leaflet perforation. FDG-PET/CT detects prosthetic valve IE with 86% sensitivity and 84% specificity but has only about 31% sensitivity on native valves. Brain MRI shows lesions, mostly silent, in 60–80%.

Antimicrobial therapy by organism

Empiric therapy for native and late prosthetic valve IE covers staphylococci, streptococci and enterococci; early prosthetic or health care–associated IE also needs methicillin-resistant staphylococci, enterococci and ideally non-HACEK Gram-negative cover (ESC 2023). Narrow once the organism is known, usually within 24–48 h, and count the course from the first negative culture, not from surgery.

Sources now differ: ESC 2023 still adds 2 weeks of gentamicin in staphylococcal prosthetic valve IE, while the 2026 AHA statement judged its kidney toxicity to outweigh any benefit, leaves rifampin to the team and says many native valve infections need only 4 weeks. Gentamicin, when used, is 3 mg/kg once daily with a trough under 1 mg/L and weekly levels and renal function (ESC 2023); daptomycin needs weekly CK (label).

POET (Iversen, NEJM 2019) randomized 400 stable patients with left-sided streptococcal, E. faecalis, S. aureus or coagulase-negative staphylococcal IE after ≥10 days IV: oral step-down was noninferior (death, unplanned surgery, emboli or relapse 9.0% oral vs 12.1% IV, followed to 6 months after treatment). ESC 2023 makes oral or outpatient completion IIa for such patients (≥7 days after surgery, TEE without abscess) but outpatient parenteral therapy Class III for hard-to-treat organisms, cirrhosis, severe brain emboli, untreated abscesses or IE from injection drug use. The 2026 AHA statement adds two doses of a long-acting lipoglycopeptide such as dalbavancin.

Surgery: indications, timing and evidence

Surgery removes infected tissue and restores the valve; ESC 2023 credits it with up to 20% better first-year survival. HF is the commonest complication and main reason for urgent or emergency surgery, then uncontrolled infection and embolic risk. ESC 2023 timing: emergency within 24 h however long antibiotics have run, urgent within 3–5 days, non-urgent in the same admission. The 2026 AHA statement favors operating within 48–72 h of an indication unless a major stroke or brain hemorrhage intervenes.

EASE (Kang, NEJM 2012) randomized 76 patients with left-sided IE, severe valve disease and vegetations over 10 mm: surgery within 48 h cut in-hospital death or embolism at 6 weeks from 23% to 3%, mostly by preventing emboli, with no difference in 6-month mortality (3% vs 5%). It underlies the 2023 Class I for a vegetation ≥10 mm with another indication; a large vegetation alone with low surgical risk is IIb.

ACC/AHA 2020 gives early surgery Class 1 for valve dysfunction with HF; left-sided S. aureus, fungal or highly resistant infection; heart block, annular or aortic abscess or destructive lesions; bacteremia or fever beyond 5 days; and relapsing prosthetic valve infection. ESC 2023 adds early prosthetic valve IE (within 6 months of implantation; I C), and infected pacemakers and defibrillators need removal of generator and leads (I B). In-hospital mortality after IE surgery is still 10–20%.

Heart block can also follow surgery: 12.8% of 444 survivors needed a pacemaker. With complete block plus prior conduction disease, S. aureus, root abscess, tricuspid involvement or previous valve surgery, ESC 2023 suggests epicardial leads at operation (IIa).

Emboli, stroke, infective aneurysms and antithrombotics

Emboli affect 20–50% of patients, up to half silently. Risk peaks around diagnosis and the first days of antibiotics and falls steeply over the first 2 weeks of effective therapy, so preventive surgery helps most when early. Vegetation length and mobility predict emboli best, with mitral location, S. aureus, S. gallolyticus or Candida, a previous embolus and growth on treatment (ESC 2023).

Symptomatic cerebrovascular events affect up to 35%, mostly ischemic stroke or TIA. Thrombolysis is Class III because septic infarcts and infective aneurysms bleed; thrombectomy may be considered where expertise is quickly available (IIb). After a TIA, or a stroke without hemorrhage or coma, ESC 2023 recommends surgery without delay when HF, uncontrolled infection, abscess or high embolic risk is present (I B); hemorrhagic conversion after surgery runs 2–7%. After intracranial hemorrhage, ESC 2023 waits more than 1 month when possible (IIa) and the 2026 AHA statement 2–4 weeks, though unstable patients may still need urgent surgery.

Infective (mycotic) aneurysms were found in 9% of patients having cerebral angiography and in up to 32% of left-sided IE on CT angiography; 36% had ruptured in a review of 499 patients. They may be silent or cause headache, seizures, focal signs or bleeding. CT or MR angiography is Class I when one is suspected, catheter angiography follows if those are negative but suspicion remains (IIa), and large, growing or ruptured aneurysms are coiled or clipped (I); coiling lets valve surgery follow the same day.

Perivalvular spread, other organs and right-sided IE

Perivalvular extension complicates 10–30% of native valve IE, more in prosthetic valves, and favors the aortic valve. The AV node and His bundle lie beneath the noncoronary and right coronary cusps, near the septal tricuspid leaflet and the mitral annulus, so a root abscess shows first as PR prolongation, then higher-grade block; EURO-ENDO found first-degree block in 8.1%, second-degree in 0.6% and complete block in 2.8% at diagnosis. New block calls for TEE or CT and, if an abscess is the cause, urgent surgery.

AKI is the second commonest complication after HF (almost 18% in EURO-ENDO), from glomerulonephritis, renal infarcts, low output, contrast and nephrotoxic drugs; 6% need dialysis, with 40% mortality. Splenic infarcts occur in about 20%, mostly silent, and up to 5% become abscesses with persistent fever, left upper quadrant pain and bacteremia; antibiotics treat most, and splenectomy for a large abscess usually precedes valve surgery. Spondylodiscitis (2–10%) causes back pain; MRI or PET/CT finds it.

Right-sided IE is 5–10% of cases, mostly on the tricuspid valve: S. aureus in people who inject drugs, coagulase-negative staphylococci more often with lines or devices. Septic pulmonary emboli cause cough, pleuritic pain and hemoptysis, and about 90% are cured medically; uncomplicated right-sided MSSA IE that responds within 96 h, with vegetations of 20 mm or less, can be treated for 2 weeks with an antistaphylococcal penicillin (ESC 2023). Surgery is Class I for RV failure from severe TR despite diuretics, respiratory failure after recurrent emboli, residual tricuspid vegetations over 20 mm after emboli, or left-sided involvement; repair is preferred (IIa).

People who inject drugs have high recurrence, especially in the first 6 months after surgery. ESC 2023 makes addiction treatment Class I and outpatient parenteral therapy Class III in this group (partial oral therapy may still help), while the AHA (2022, 2026) puts addiction medicine on the team, supports medication for opioid use disorder and offers long-acting lipoglycopeptides when IV access is unsafe.

Regurgitant emergencies: papillary muscle rupture and acute AR

Acute regurgitation loads a ventricle and atrium that have not dilated. In acute MR the stiff left atrium passes each jet to the lungs: flash pulmonary edema, large v waves on the wedge trace, and a murmur that may be soft or absent because LA and LV pressures equalize. Papillary muscle rupture (0.05–0.26% of MIs) follows inferior or lateral MI on days 3–5 and carries 10–40% hospital mortality; it is nearly always the posteromedial muscle, which has a single blood supply (AHA 2021). In IE, leaflet perforation or chordal rupture does the same.

The bridge sends blood forward: nitroprusside or nitroglycerin when MAP allows, an inotrope for low output, diuretics and positive pressure for edema. An IABP lowers afterload and the regurgitant fraction; an Impella unloads the LV but must clear the mitral apparatus; VA-ECMO is salvage and needs LV venting (Miller 2024). Rupture is a surgical emergency, and over 70% of patients needed mechanical support before surgery (AHA 2021; support as a bridge is 2a in the 2025 ACC/AHA ACS guideline). Transcatheter edge-to-edge repair is an option when surgery is not.

Acute severe AR (IE, type A dissection, trauma) fills the LV from the aorta as well as the atrium. LVEDP rises fast and can close the mitral valve early, so pulse pressure may not widen and the diastolic murmur is short and soft. Faster rates shorten diastole and the regurgitant volume, so bradycardia and β-blockers are dangerous except for cautious use in dissection; pacing at a higher rate has been used. Nitroprusside is first line when BP allows; hypotensive patients tolerate norepinephrine or epinephrine better. An IABP or peripheral VA-ECMO raises aortic diastolic pressure and worsens the leak; urgent surgery is the treatment (Miller 2024).

Obstructive emergencies and LVOT obstruction

Severe AS is a peak velocity ≥4 m/s or a mean gradient ≥40 mm Hg, usually with a valve area ≤1.0 cm² (ACC/AHA 2020). The thick, stiff LV needs filling pressure and atrial kick, and its hypertrophied muscle is perfused only while diastolic pressure holds, so hypotension starts an ischemic spiral. Keep preload, treat AF promptly (cardioversion if unstable) and support pressure with phenylephrine or norepinephrine; inotropes can raise the gradient and provoke arrhythmias, and induction with positive pressure can collapse preload (Miller 2024).

The vasodilator exception: in 25 patients with severe AS, LVEF ≤35%, CI ≤2.2 and MAP ≥60, nitroprusside under invasive monitoring raised CI from 1.60 to 2.22 L/min/m² at 6 h (Khot, NEJM 2003). Definitive care is valve replacement. In the STS/ACC TVT registry (about 300,000 TAVRs, 2015–2022), 5,006 patients in cardiogenic shock had 30-day mortality of 12.9% vs 4.9% but similar 1-year mortality; balloon valvuloplasty is a rescue bridge, with 30% early mortality in one 40-patient series (Miller 2024).

In rheumatic MS (severe at a valve area ≤1.5 cm²), LA pressure rises with flow and with shorter diastole, so tachycardia, AF, fever, anemia and pregnancy bring on pulmonary edema. Slow the rate with a β-blocker (or a nondihydropyridine calcium channel blocker or digoxin), restore sinus rhythm when possible, avoid hypoxia, hypercarbia and acidosis that raise PVR, and support pressure with phenylephrine with or without vasopressin (Miller 2024). AF with rheumatic MS needs a VKA: in INVICTUS (NEJM 2022; 4,531 patients) rivaroxaban led to more events (560 vs 446) and more deaths. Balloon commissurotomy suits favorable valves, even in critical illness.

Mechanical valve thrombosis (0.1–5.7% per patient-year) usually follows a low INR and presents as dyspnea, HF, emboli or muffled clicks; echo, fluoroscopy or CT confirms it. ACC/AHA 2020 gives urgent slow-infusion low-dose fibrinolysis or emergency surgery Class 1 for obstructive left-sided thrombosis; ESC/EACTS 2025 favors surgery for operable patients with a large thrombus or emboli and keeps lysis for high surgical risk or right-sided valves. Alteplase runs 25 mg over 6 h or 25 h without a bolus, repeated after imaging. In HATTUSHA (JACC 2022; 158 patients) lysis succeeded in 90.4%, with 3-month mortality 2.4% vs 18.7% after surgery; in SAFE-PVT (Eur Heart J 2025; 79 randomized) the primary outcome did not differ and deaths were 1 with lysis vs 7 with surgery, but 25% had residual valve dysfunction after lysis.

Dynamic LVOT obstruction occurs when a small, hyperdynamic LV drags the anterior mitral leaflet into the outflow tract in systole (SAM), adding posteriorly directed MR. Beyond HCM it follows mitral repair or AVR and appears in apical ballooning and in dry patients on catecholamines; suspect it when BP falls as dobutamine rises, and confirm SAM and a late-peaking gradient on echo. Stop inotropes and vasodilators, give fluid, add a β-blocker (esmolol, or IV metoprolol 15 mg over 15 min in Sherrid's series) and phenylephrine; IABP deflation lowers afterload and can worsen obstruction (Sherrid, JAHA 2021).

Obstructive HCM therapies with ICU consequences. Mavacamten, a cardiac myosin inhibitor, lowers contractility; it is interrupted if LVEF falls below 50%, its label says to avoid disopyramide, ranolazine, and verapamil or diltiazem with a beta-blocker, to consider interruption during intercurrent illness, and to delay dose increases with arrhythmia such as AF. Alcohol septal ablation, the alternative to myectomy for older or higher-surgical-risk patients, causes more complete heart block and repeat procedures than myectomy (Merck); in one series 61% developed new RBBB, 22% had transient complete heart block during the procedure and one patient needed a pacemaker for block that appeared after 24 h (Mani 2021), so monitor rhythm closely afterward.

Nursing care, monitoring and teaching

• Neuro: frequent checks of consciousness, speech, pupils and strength; a new deficit or severe headache is a stroke alert, with no lytics.
• Cardiac: new or louder murmurs, HF signs, and the PR interval on serial ECGs in aortic IE; report new block at once.
• Infection: cultures before the first dose and until negative; first-dose times; fever, WBC and CRP trends; PICC or central line care.
• Kidneys and drugs: daily creatinine and urine output; vancomycin and gentamicin levels; hearing and balance on aminoglycosides; CK on daptomycin.
• Emboli: left upper quadrant or flank pain, hematuria, a cold limb, chest pain or ST change.
• Anticoagulation: hold or convert to UFH as ordered when surgery is likely; rifampin lowers warfarin's effect, so check the INR often (label); INR on target before discharge for mechanical valves.
• Pain and addiction: treat pain adequately, offer medication for opioid use disorder and harm reduction, and plan safe IV access.

Teach daily oral hygiene and regular dental care. Prosthetic valves, prior IE and certain congenital disease warrant antibiotic prophylaxis before dental work that manipulates the gums (AHA 2021, ESC 2023). Recurrence runs 2–9%, so patients report any fever after discharge.

Exam pearls

• Three blood culture sets before antibiotics; TTE first, then TEE for prosthetic valves and abscess.
• S. aureus is the commonest cause; injection drug use means tricuspid S. aureus IE with septic lung emboli.
• Janeway lesions are painless and embolic; Osler nodes are painful and immune.
• New PR prolongation or heart block in aortic valve IE means a root abscess and urgent surgery.
• Surgery for HF from valve failure (emergency if shock), uncontrolled infection, or a vegetation ≥10 mm with emboli.
• No thrombolysis or new antiplatelets in IE; thrombectomy may be considered.
• IABP helps acute MR, is contraindicated in AR and can worsen LVOT obstruction.
• Aortic stenosis: keep preload, sinus rhythm and SVR; phenylephrine for hypotension; avoid nitrates.
• Mitral stenosis: slow the heart; warfarin, not a DOAC, for AF.
• LVOT obstruction with SAM: stop inotropes, give fluid, a β-blocker and phenylephrine.