**11.1. Surgical valves**

the mitral is most commonly affected. Stenosis is more commonly present at the mitral valve

The revised Jones Criteria [69] for diagnosis of ARF, importantly has now incorporated Doppler echo for both acute and chronic valvulitis. In the previous guideline (1992), cardiac involvement was based on clinical auscultation. Modern-era echo has been validated for diagnosis of subclinical carditis. Echo may either help confirm or exclude carditis when a murmur is present, or it may detect subclinical carditis. The most common cardiac changes are cardiac valve involvement (valvulitis) and may be accompanied by a pancarditis with or without a

With acute rheumatic mitral and aortic valvulopathy, functional and haemodynamic changes are readily diagnosed by Doppler echocardiography. The regurgitation must be demonstrated in at least 2 views with a peak jet velocity of >3 m/s, a pan systolic or diastolic jet respectively and a jet length of ≥2 cm for MR and ≥1 cm for AR. Morphological changes may or may not be present early during infection [69]. The morphological change(s) seen at the MV during acute valvulitis/carditis include: (i) annular dilatation, (ii) chordal elongation/rupture, (iii) leaflet prolapse and/or (iv) beading/nodular thickening of the leaflet tips. Chronic changes of the mitral valve apparatus include: (i) thickening of the leaflets/chords, (ii) chordal fusion, (iii) restriction of leaflet motion and/or (iv) calcification [69]. Acute and chronic aortic valve changes of rheumatic valvulitis/carditis demonstrated with 2-D echo include: (i) irregular and/or focal thickening of the leaflets, (ii) leaflet retraction/restriction with or without coapta-

Incidence of IE in persons with RHD is 3.8–440 per 1000 patient-years [61]. Data published from the National Health Service in England [70], revealed a marginally lower incidence of 3.05 cases per 1000 patient-years, compared with nonrheumatic valve disease at 2.73 per 1000 patient-years in the same study. The incidence of IE in rheumatic mitral stenosis is estimated at 0.17 per 1000 patient-years. Severity of valvular haemodynamics in RHD and risk of IE is

Intravenous drug use (IVDU), along with cardiac-devices, CHD and vascular access catheters, are the major risk factors for RSIE. Right-sided IE constitutes 5–10% of IE cases and approximately 90% of RSIE involves the TV [71]. Overall, IVDU use accounts for 5–10% of all cases of IE [3, 72]. The median age at time of infection is 30–40 years, not infrequently seen in patients

and regurgitation involving the aortic [49].

tion defects and/or (iii) leaflet prolapse [69].

*9.2.2. Risk of endocarditis*

not well described.

**10. Intravenous drug use**

myopericarditis [69].

30 Advanced Concepts in Endocarditis

**9.2. Echocardiographic diagnosis of rheumatic heart disease**

*9.2.1. Echocardiographic diagnosis: Doppler haemodynamics and 2D features*

The estimated risk of prosthetic valve endocarditis (PVE) overall is 0.3–1.2% per patient year (3–12 per 1000 patient-years) [57]. Recent study data from the National Health Service in England [70] reported an incidence of 4.64 cases per 1000 patient-years. In a landmark early study from the 1980s, the risk for mechanical valve IE was shown to be higher in first 3 months post-surgery, whilst for porcine valves, the IE risk was higher >12 months. The cumulative risk by 5 years was not significantly different between mechanical and porcine [79].

A large study recently published, incorporating contemporary valve data, has found bioprosthetic valves do carry a higher risk for IE than mechanical valves, with a multivariableadjusted hazard ratio of 1.65 (CI, 1.16–2.37) for early (<12 month) and 1.53 (CI, 1.25–1.86) for late (>12 months) IE. The crude incidence rates were 11.7 vs. 7 per 1000 patient-years for early IE and 6.0 vs. 4.3 per 1000 patient-years at 1–5 years (post-surgery) for bioprosthetic and mechanical valves, respectively. Similar rates were seen out to 15 years of follow-up in both groups. The overall combined incidence for PVE was 0.57% (5.7/1000) per patient-year [80]. It was suggested structural deterioration of prosthetic valves is a contributing risk factor, but this requires further investigation. Another study found a higher risk of IE with bioprosthetic over mechanical AVR, where the incidence of re-hospitalisation for IE was at 2.2% versus 1.4%, over 12 years follow-up, with adjusted hazard ratio of 1.6 (CI, 1.31–1.94). This difference was seen across all groups, except those aged 75–80 years and patients with renal failure [80].

Implantable pacemakers (PPM) and cardiac defibrillators (ICD) have a reported incidence of IE ranging from 0.68–1.9 cases per 1000 patient-years [57, 70]. Cardiac device-related infective endocarditis accounts for 10–23% of device infections [85]. Numerous risk factors have been identified, including previous device-related infection, however information on risk related to underlying structural cardiac or TV pathology is uncertain. From the ICE-PICS data [86], 6.4% of all cases of IE were CDRIE. Over one-third of cases had associated valvular involve-

The Role of Modern-Era Echocardiography in Identification of Cardiac Risk Factors for Infective…

http://dx.doi.org/10.5772/intechopen.75760

33

One of the most important cardiac risk factors for endocarditis is a prior history of IE. In the ICE- PCS cohort, recurrent IE occurred in 4.8% of patients, given an odds ratio of 2.8 (CI, 1.5–5.1) [87]. This is concordant with findings from other published studies with rates between 3.3 and 11.7% [88, 89]. In a recent study, the risk for recurrent IE was 14.36 per 1000 patient-years [70]. In a different study, the risk of recurrence (in patient-years) was estimated as follows: (i) history of previous IE, 7.4 per 1000, (ii) prosthetic valve surgery for native valve IE, 6.3 per 1000 and, (iii) prosthetic valve surgery for prosthetic valve IE, 21.6 per 1000 [61]. In a meta-analysis comparing biological versus mechanical valve for IE surgery, recurrence of IE in mechanical valves was 3–9% and for biological valves 7–29% [90] . Other studies have

Renzulli et al. [91], interestingly reported there was no association with previous perivalvular extension and recurrent risk [91]. In a study focussing on aortic homografts, Flameng et al. [92] found the recurrence rate of IE was relatively low at 7% at a mean follow-up of 8 ± 5 years. A significant downside is the high rate of structural deterioration of aortic homografts, with

Shimokawa et al. [93] reviewed long term outcomes of mitral valve repair following IE in patients with prolapse and found good outcomes when compared with repair for degenerative MVP without IE. In this study, there were no recurrences of IE [93]. In another metaanalysis, comparing MV replacement with MV repair in the setting of IE, the 5 year risk of

The three main categories of cardiac disease predisposing to infective endocarditis are degenerative valve disease, congenital heart disease and less commonly in high-income countries, rheumatic heart disease. The changing epidemiology has been associated with an ageing population, increased prevalence of prosthetic valves, devices and shunts, and health-care exposure. This chapter has outlined the underlying pathology, risks and echocardiographic predictors for IE associated with a selection of lesion-specific cardiac pathologies. The chapter also addressed the observation of structurally 'normal' cardiac valves accounting for a rising proportion of IE cases. Whether this relates to microorganism virulence, host factors, early structural and

ment, most commonly the tricuspid valve.

a rate of 40% at 10 years [92].

**12. Conclusion**

**11.5. Recurrent native and prosthetic valve infective endocarditis**

found equal rates of reinfection of bioprosthetic and mechanical valves.

recurrent IE was favourable in the repair group with OR 0.39 (0.10–1.58) [94].

#### **11.2. Valve repairs**

Valve repairs with prosthetic material carry a reported incidence of 4.71 cases per 1000 patient years [70]. In a pooled analysis (24 studies), recurrence of IE after mitral valve repair versus surgical replacement was 1.8% compared to 7.3% (p 0.0013), with a mean follow-up of approximately 50 months [81].

#### **11.3. Transcatheter valves**

The incidence of IE in transcatheter aortic valve replacement (TAVR) is similar to surgically placed prosthetic valves. There is no reported significant difference between self-expanding and balloon-expanding IE rates. Residual moderate or severe regurgitation was associated with higher rates of IE at 16.3 per 1000 patient-years versus 9.3 per 1000 patient-years for mild or no aortic regurgitation [82].

For pulmonary transcatheter valve (Medtronic MelodyTM), one study [83] reported a rate of IE of 3% per patient-year for a median follow-up of approximately 2 years. With regard to valvedconduits, the incidence of IE with RVOT homografts was lower at 0.8% per patient-year compared to Contegra-Melody conduit rate of 2.7–3.0% per patient-year. In patients with an infected Melody valve, 4/8 had a peak gradient >40 mmHg, whilst only 5/99 in the non-IE group had a similar gradient (p < 0.05) [83]. This suggests a possible increased risk of IE with residual post-procedural gradients, but numbers are insufficient and further studies are required to confirm or refute this assertion.

#### **11.4. Device-related endocarditis**

Ventricular assist devices (VADs) carry an incidence of IE of 5.8 cases per 1000 patient-years [70]. In one study investigating VAD infections, the following rates (cases per 100 LVADyears) were found: i) all infection types –32.8 (CI, 26.7–39.9), ii) IE 1.6 (CI, 0.5–3.8) and iii) bloodstream – VAD-related, 7.5 (CI, 4.7–11.2) [84].

Implantable pacemakers (PPM) and cardiac defibrillators (ICD) have a reported incidence of IE ranging from 0.68–1.9 cases per 1000 patient-years [57, 70]. Cardiac device-related infective endocarditis accounts for 10–23% of device infections [85]. Numerous risk factors have been identified, including previous device-related infection, however information on risk related to underlying structural cardiac or TV pathology is uncertain. From the ICE-PICS data [86], 6.4% of all cases of IE were CDRIE. Over one-third of cases had associated valvular involvement, most commonly the tricuspid valve.

## **11.5. Recurrent native and prosthetic valve infective endocarditis**

One of the most important cardiac risk factors for endocarditis is a prior history of IE. In the ICE- PCS cohort, recurrent IE occurred in 4.8% of patients, given an odds ratio of 2.8 (CI, 1.5–5.1) [87]. This is concordant with findings from other published studies with rates between 3.3 and 11.7% [88, 89]. In a recent study, the risk for recurrent IE was 14.36 per 1000 patient-years [70]. In a different study, the risk of recurrence (in patient-years) was estimated as follows: (i) history of previous IE, 7.4 per 1000, (ii) prosthetic valve surgery for native valve IE, 6.3 per 1000 and, (iii) prosthetic valve surgery for prosthetic valve IE, 21.6 per 1000 [61]. In a meta-analysis comparing biological versus mechanical valve for IE surgery, recurrence of IE in mechanical valves was 3–9% and for biological valves 7–29% [90] . Other studies have found equal rates of reinfection of bioprosthetic and mechanical valves.

Renzulli et al. [91], interestingly reported there was no association with previous perivalvular extension and recurrent risk [91]. In a study focussing on aortic homografts, Flameng et al. [92] found the recurrence rate of IE was relatively low at 7% at a mean follow-up of 8 ± 5 years. A significant downside is the high rate of structural deterioration of aortic homografts, with a rate of 40% at 10 years [92].

Shimokawa et al. [93] reviewed long term outcomes of mitral valve repair following IE in patients with prolapse and found good outcomes when compared with repair for degenerative MVP without IE. In this study, there were no recurrences of IE [93]. In another metaanalysis, comparing MV replacement with MV repair in the setting of IE, the 5 year risk of recurrent IE was favourable in the repair group with OR 0.39 (0.10–1.58) [94].
